It's impossible to know what everyone is running, but I would assume there will be some transports in play. You would be better off not running lash princes. Lash is just fun on a bun when you're dealing with foot troops, but chances are the princes will have to get in and
cc rhinos to death, and then if they don't get shot/killed by the vehicle contents they will be in assault next turn, rendering the lash useless. If you run a Nurgle prince (pref with wings) you get a Ws7 S6 T6 I5 beast. run that through the same scenario and they survive the shooting and what have you, and then proceed to wreck face. The
init bonus
MoS would give you should be pointless, as a prince with any other mark will be going first most of the time. Daemon Princes are bullies. If they are fighting things as awesome or awesome-er than they are, you're doing it wrong.
Lose the dreads. They can be fun, unless they shoot your own stuff for three rounds. Also they have dread
ccws, but they have a Ws4. They will end up standing in one place the entire game tied in an endless
cc. They will generally kill whatever they hit, if they hit it, and take into account they will be losing attacks as their arms get blown off, and they will. If you are going to run dreads give them some real armament. TLL is a nice choice.
I'd lose the regular
CSMs and the SLDs and take a decent unit of any other troop choice. it's worth the extra points for fearless and a mark of whatever.
Now if you are going to run SLDs for sure no matter what you may consider running several smaller units of them. Seeing as how you have no reserve manipulation there's no telling when they will come out, and you could use late comers in turn 4 or 5 to snag objectives, or simply contest them. If There are no objectives run 15-20 and call it a day. They are like dirt cheap berserkers with invul saves, sans the furious charge.
Go go Plague Marines. Maybe swap a plasma for a melta... or two plasmas for two meltas... i typically run six.
Love the oblits, but don't run them as solos. They are slow. If you place one with a crappy
LoS, he may never get to do anything. Go ahead and run them at least in squads of two. They also have some nob-like survivability in
cc at that point.
Lose the heavy armor and go ahead and spring for possession on the rhinos.
From the ground up if you want to run a truly chaotic list I'd run a ton of SLD, Kharn the Betrayer, a sorcerer lord with Gift of Chaos, 2 squads of berserkers, 2 Dreads, some possessed, and some vindicators. It's all of the randomness you could possibly ask for. It
WILL NOT win. But it could be fun.
What you have here isn't a terrible list, but the cheese list guys will eat you alive.