Hey there
I am also getting back into the hobby. What a great time for it!
I drafted a 1000 point almost identical to yours and after a couple of test games here are my thoughts:
- Razorbacks w/ twin assault cannons are pretty amazing! Especially when positioned within the 6" Rites of Battle bubble from the Captain. The only issue is range, as first turn you are most likely beyond 24" unless you move the tank, which reduces
BS.
- Captain's (I ran Vulkan

because i play salamanders) stand out feature was Rites of Battle. I made sure most of my units where within 6" to get the rerolls (I'm pretty sure it applies to himself as well but don't quote me on this

. He's not bad in combat as well.
In my list i ran 5 sniper scouts to snipe buffing characters like commissars and painboyz. First game they did diddly squat but second game took out an ork painboy first turn.
My suggestions:
I find Tacticals to be a bit lacklustre so i would swap out the 10 man squads for 5 man combat squads. load out with plasma gun, combi-plasma, chainsword (may just bring it over 750 points). I would definitely consider not embarking based on the scenario to increase ranged firepower and benefit from the Captain.
Use the points gained for a 5 man devastator squad w/ 4x missile launchers and armourium cherub giving versatile anti-tank and horde control. these guys can be vulnerable to deep striking and outflanking units.
Dreadnought looks solid, venerable upgrade looks good points permitting
All in all very solid list you posted, let me know how it fares!