I assume the enginseer is babysitting the hellhammer to repair it? Needed in my view as Baneblade variants are too expensive for their points imo. They just don't get any save - the conscripts won't give the Hellhammer a cover save for intervening models, they'll just prevent a charge against it. Your opponent can either deal with it and it's gone by end of turn 2, or they can't and it's ignored. usually it's the former. Anyway moving swiftly on ...
I think a commissar is almost certainly needed for the conscripts.
It's an interesting one as I haven't really played with the assassins, but the mass of guard just looks too squishy. However, it may be the assassins tank the anti-infantry fire, but I can just see your troop choices disappearing off the board without a Lord Commisar to hold them. I don't see your infantry doing a lot to be honest.
There's no anti flyer in there, which may be deliberate.
There's also very little anti tank. The auto cannons can do light tanks, but HWT don't usually last long. You only have two main anti tank shots on the Hellhammer, and you may be wanting to use the main gun to flush out infantry in cover?
Not sure if any of the assassins are useful antitank. You've also got no psykers to boost your psyker assassin so that one may be a bit of a waste?
Like I said I'm not really up to speed with the assassins so maybe they do cover the gaps well? Also what does the inquisitor actually do? Anyway like you said it's a fun list.
I'm not a huge fan of super heavies as I feel like you need to agree it in advance and then the other guy thinks "Hmm, I'll just take sternguard meltas in a drop pod". Hopefully when the new guard codex comes out with formations etc, baneblades and their variants will be in it and they'll have reduced the points cost for them. Personally I'd rather go multiple russes. But that's just me. For what it's worth I think the Hellhammer is the best variant.