To list critique, Battlecannons + Lascannons isn't that great, damn'd loss of Lumbering Behemoth!
It looks to be gunline, and if so, I can assure you that an Aegis is worth it's weight in gold to add that extra "Up yours" when someone is shooting at a Russ, or your infantry, or anything at all.
Even if not, if half your army is sitting still it's worth it.
Without a Lord Commissar, I wouldn't take HWT's as they're expensive and obscenely fragile. You're probably going to want them near the back of your DZ, so a single failed Ld test [42% of the time] after 2 [!] wounds and they basically run off after being shot by a 5 man squad, or get wiped by a full squad shooting at them. Better off with a pair of Sentinels with AC's, for the points. Tougher, provide better speed-bumping, and they're mobile.
Without a Ld boost character, I'd advise against blobbing infantry, as they're safer speed-bumping for each other.
If you're into the fluff behind the Vostroyans, they come with Carapace armour and "Artisanal" Lasguns, best represented by Carapace Vets. Carapace Vets also happen to be amazing. In my mind, Carapace is an auto upgrade for competitive Vet building. Maybe just my metagame, but it is my honest experience. To that end, were I to incorporate that idea, I'd go with a dual FOC build... sorry that the points are off a bit, Codex is an hour away.
FOC#1: 930 ish points
CCS: Lascannon, MoO, Vox,
Kurov's Aquila,
Chimera MuL, HB
Vets: Carapace, Boltgun, 3x PG, AC, Vox
Vets: Carapace, BG, 3x PG, AC, Vox
LR Executioner: Lascannon, 2x PC
LR Vanquisher: LC, 2x MM
Hydra:
FOC#2: 820 ish points
CCS: 3x Melta, Vox,
Chimera MuL, HF
Vets: Carapace, BG, 2x Melta, 1x Plasma, AC, Vox,
Chimera Mul, HF
Vets: Carapace, BG, 2x Melta, 1x Plasma, AC, Vox,
Chimera Mul, HF
LR Demo: HB
LR Exterminator: LC, 2x MM
Hydra:
** I forgot to put Carapace on the CCS squads. Need points shaved from somewhere to accommodate fluff. **
FOC #1: Kurov's Aquila effectively reduces overheat damage to next to nothing. Carapace keeps you alive if you're short on cover, or you get hit with flamers. Sit'n'shoot units need to be able to engage all varieties of targets. They don't get to choose what they shoot, your opponent does.
Russes flank the CCS to prevent LOS to the weak flanks of the Chimera. If you can work in an Aegis, you're laughing, hard, at anything that tries to hurt them. With orders, you can split the AC's off from the Infantry, to try to pop a whatever. Add some snaps to firing at that annoying flyer!
FOC 2:The Vets are able to engage at all ranges, maximising their damage output from within the Chimera. Long range? Plasma + AC vs vehicles [even if moving, snaps aren't bad] or Plasma + BG against infantry. Up close? Double tap vs light infantry, or Melt that vehicle, or take 3 shots against Elite infantry / MC. Limited fire points rewards mixed weapon load-outs. Forget the flamer, you've got a heavy flamer on the front of your tank, and the short range matters for wound stacking.
Move the Exterminator up with the rest of FOC #2. That ensures you have med/light vehicle opening available to increase the effectiveness of the Demolisher. Open a can, splat the sardines, wipe up the leftovers. That load out is also handy for Flyer tagging. Not great, but a good secondary plan. Tertiary role in elite-infantry / MC hunting.
If you're into cheese, and still don't like an Aegis, the Stronghold rules have those Battlecannon turret buildings for something like 80 points each? Two BC for the price of one LRBT.