So, here are most of the changes from the new index, let me know if I missed anything:
GENERAL STUFF:
-We have no Interromancy discipline as of right now, although Ezekiel's datasheet seems to mention it (maybe some kind of copy/paste error?).
-We no longer have access to any of the
DA strats from the old codex, although many from the
PA book are here and available to us (losing Weapons from the Dark Age, Intractable, and Speed of the Raven hurts, but maybe we'll get some version of those back when we get the full supplement).
-We also lost our old codex relics, but retained most of the ones from the
PA book, including the special issue wargear ones. RIP Heavenfall blade, at least until the full book comes out.
-We retain the Ravenwing and Deathwing Warlord Traits from the
PA book, but have lost the others except for Brilliant Strategist (which is in the main Marines book). One of the Deathwing ones is oddly missing though.
-Jink now confers a 5++ vs. ranged attacks on units that moved and a 4++ on units that advanced (with the relevant keywords). Definitely a buff there. Oddly,
RAW it doesn't seem to go to stuff from the main Marines book even though certain units in that book gain the Ravenwing keyword (like Outriders or even regular bikes/attack bikes). Time will tell if that was an oversight or a deliberate omission.
-Inner Circle changed a lot. It still grants auto-passing morale, but now it makes it harder for INNER CIRCLE units to fall back from enemies (they have to roll vs. leadership), and impossible to fall back from FALLEN units, if that matters ever. The big news is that we basically have Transhuman Physiology baked in on all our Deathwing Infantry (except, again, ones from the main book like Bladeguard and Relic Termies)!
UNIT CHANGES:
Azrael: 170 pts. (up from 160 in the MFM): His plasma always uses the supercharged statline and never overheats, which is a definite plus. His full-reroll ability is no longer an aura, but rather a one unit per turn ability (pretty sure that's common to all Chapter Masters). His sword is now flat 2 damage but otherwise the same. Still has the 4++ bubble for Infantry and Bikes. *Update* Now grants 2
CP if he is your Warlord, and his invulnerable save bubble is now restricted to ranged attacks only, a slight nerf.
Belial: 140 pts. (up from 125 in MFM): He now has the Chapter Master full reroll ability for one unit but only for Deathwing (as expected). He now carries a Master Crafted Storm Bolter (
AP-1, D2) and his sword is now D3 (nasty!). All the other stuff is the same as before.
Sammael: 150 pts. (up from 140 on Corvex): The big thing to say is he seems to no longer be able to take Sableclaw and is stuck with the jetbike. Moment of silence please for that awesome gunboat.

That said, his bike got a slight upgrade in that, like Azrael's plasma, his always uses the overcharged statline and doesn't kill him if it misses. He also got the
CM thing except for Ravenwing. He also has 8 wounds now, which I'm pretty sure is more than he had before (think it was 6 on Corvex and 7 on Sableclaw).
Ezekiel: 125 pts. (up from 115): Big change is his aura is now basically what Asmodai's used to be (+1 attack for Dark Angels Core or Characters), except it specifically says it doesn't stack with Shock Assault. His sword got slightly better like all swords did. Still knows Smite and 3 powers, casts 2, and denies 2, although as I said earlier Interromancy seems to be gone for now so he has to take Librarius. The fact that it says he gets +1 to cast Interromancy powers suggests that we'll be getting it back with the full supplement release though.
Asmodai: 130 pts. (up from 115): His aura is now basically a buff to the Litany of Hate (+1 to cast and +3" bubble for it). Another change seems to be for all Interrogator-Chaplains: They now count all enemy units as below half strength for the purpose of Combat Attrition tests. His crozius got buffed as per standard for Chappies, and his Blades of Reason is now an extra attack with its profile (and he can't choose to make more attacks with it, just the one).
Lazarus: 110 pts. (same as MFM): As far as I can tell he didn't change at all.
Interrogator-Chaplain: 85 pts. for
PA, 100 in Terminator Armor (
PA same, Terminator down from 105): Pretty much the same except for the change to the Aura of Dread (see Asmodai above). Still knows Litany of Hate and one other Litany and can only recite one per turn. Jump Pack still costs 25 points for the
PA version, and all the wargear pretty much costs the same as in the MFM, except that Storm Bolters for the
PA version cost 5 and somehow combi-weapons also only cost 5.
Ravenwing Talonmaster: 160 pts. (down from 175): The power sword and heavy bolter changes are as standard and already known. The twin assault cannon is also the same as before. The Lieutenant buff now only affects Core units (as expected), and the ignore cover aura is restricted to Ravenwing Core units (again, as expected). His number of attacks went down from 4 to 3, but he now has 8 wounds where he used to only have 6. His
BS also went up to 2+, making Corvus Occulus less of an auto-pick (but still pretty handy). Not too shabby I think; Talonmasters may still be fairly popular in
DA lists. One other thing; they are Lieutenants and therefore you can take 2 in a single detachment slot!
Deathwing Apothecary: 100 pts. (up from 78): The changes here are pretty much the standard Terminator and Apothecary changes from the new Marines codex. The only other change is the fact that he doesn't take up a detachment slot if you have one of the new Deathwing Command Squad units in the same detachment.
Deathwing Champion: 80 pts. (down from 85): Pretty sure most of the changes here are the same as normal Champions in the Marines book. The Halberd now allows him to make extra swings at enemy units of 10 or more models, which is nice.
Deathwing Ancient: Missing, hopefully an oversight and not a purposeful deletion...

Update: Apparently he's now just a standard Ancient in Terminator Armor in the Marines codex.
Deathwing Terminator Squad: 33 pts./model (down from 36/model): Wargear is the same as always with the standard changes from the Marines book. They got the 3rd wound, again as we knew would happen. Watchers in the Dark now give the unit a once-per-game Deny the Witch attempt.
Deathwing Knights: 47 pts./model (up from 45): 3 wounds now and the same change to Watchers in the Dark. They are also
BS/
WS 2+, which could be massive.
Deathwing Command Squad: 35 pts./model: New unit, works a lot like Company Veterans as far as unit size, with same wargear options as standard Deathwing Termies. They also get a bodyguard rule for Deathwing characters.
Ravenwing Apothecary: 100 pts. (up from 65): Main changes are same as other Apothecaries, although now he comes with an Astartes Grenade Launcher as standard (which he can swap for a Plasma Talon at no cost). Like the Deathwing characters above, he has the Command Squad ability, except that it requires a unit of Black Knights instead of a bespoke Command Squad unit.
Ravenwing Champion: 70 pts. (down from 75): Same basic changes as the Deathwing Champion as far as Champion abilities (always fights first, 6" heroic intervention, etc.). One loss which will be keenly felt on our Ravenwing as well as regular champions is that they no longer get a special sword (Blade of Caliban), but rather a standard master-crafted power sword. Like the other Ravenwing characters, he can choose between a Plasma Talon or Astartes Grenade Launcher, and he doesn't take up a slot if you have a unit of Black Knights in the same detachment.
Ravenwing Ancient: 100 pts. (up from 85): Mostly unchanged statwise, and has the same options as the other two Ravenwing guys as far as gear/detachments. The banner got swapped for a standard Astartes banner instead of the +1 attack buff, which hurts. Could still be nice to have your Black Knights getting in a couple of final plasma shots if and when they eat it, and he can take the relic banner.
Ravenwing Black Knights: 40 pts./model (same as before): These are now apparently Elites instead of Fast Attack for some reason. They got the third wound that the regular bikers got, which is very nice, but the big change is that, while the cost is the same as before, they now have to pay 5 points per model if they want to carry their Corvus Hammers. Ouch. That said, it's probably worth taking the hammers as they are now D2 standard, meaning that these guys are now pretty dangerous in combat, especially against
MEQ.
Ravenwing Darkshroud: 130 pts. (down from 135): Very little has changed for this thing; it now costs an extra 5 pts. to swap its Heavy Bolter for an Assault Cannon. One anomaly in the Index is that the datasheet shows it as an Elites choice but the point costs page lists it as Fast Attack, which it was before. Odd.
Ravenwing Land Speeder Vengeance: 120 pts. (same as before): The vehicle itself has not changed, but its main plasma weapon now fires 2d3 shots and, when supercharged, takes a mortal wound for each unmodified hit roll of 1 rather than disabling the gun, which perhaps makes it playable now. Like the Darkshroud, it can pay 5 pts. to upgrade to an Assault Cannon (is it an upgrade though?), and it shows as Elites on the datasheet and Fast Attack on the points page.
Ravenwing Dark Talon: 210 pts. (down from 215): Lost Strafing Run, which hurts but was not unexpected with the 9th edition changes. Rift Cannon now deals 3 mortal wounds on a successful wound roll instead of normal damage, and the Stasis Bomb is now an automatic d3 mortal wounds and prevents the target unit from falling back this turn (still once per game). The plane now has 11 wounds for whatever reason too.
Nephilim Jetfighter: 190 pts. (up from 170): Also lost Strafing Run and gained a wound. Avenger Mega Bolter is now S5 and D2. Blacksword Missiles now
AP-3 and
D4 against enemy AIRCRAFT units. The unit itself has +1 to hit enemy AIRCRAFT.
My takeaways:
-Deathwing are going to be disgusting with their built-in Transhuman Physiology. Even anti-tank weapons are going to struggle to hurt them, especially the Deathwing Knights with their 4++. I'm definitely thinking that Deathwing Terminators could be very annoying midfield objective takers since they are not easy to shift in melee or shoot off of an objective, and their shooting can be pretty gross if they are in Tactical Doctrine (all those
AP-1 storm bolters).
-Ravenwing could be pretty solid, as they have mobility to go out and grab objectives as well as some of them being able to credibly flip an objective that the opponent is holding (D2 Corvus Hammers for the win there). Pair them with a few Deathwing and use Combined Assault to really bring the pain! Talonmasters can clear a drop zone to land some Terminators, too.
-The flyers actually have me intrigued. Both of them can make good use of the new Jink rule (they both have it), which can protect them somewhat from anti-tank weapons. Dark Talons can start the Mortal Wound pain train better than before, but the stasis bomb is a bit weaker than before
IMO. The Nephilim is probably going to be one of the more efficient
MEQ killers in our arsenal, but it may not be worth its points now. I'm pretty sure flyers can be useful for certain positional secondaries (Engage on All Fronts), although they can't actually secure objectives at all.
-Talonmasters are still cash money, especially since they are getting a price drop. Lack of rerolls hurts, but then that was kind of
OP before. Being able to take 2 in a single
HQ slot means you don't have to sacrifice other buff characters to get them.
-Our go-to Warlord Trait is going to be Brilliant Strategist. Holy gak Brilliant Strategist. The ones from this Index just don't come close to being as universally good as that.
-The Relics from this book are kind of lackluster overall. Corvus Occulus is going to be a strong pick, but otherwise? Maybe a few of the regular Marine ones could be useful for us (Teeth of Terra, assuming that's still a thing). The Deathwing banner could be good as well for making those jerks even more tanky and is probably an auto-include if you're going deep on Deathwing.
-We're gonna be hurting for strats, or are we? We got some good ones in the main Marines book, plus the ones in this Index. We can live without WftDA for a little while at least.