for start leave assault squad and take 2nd ful tac squad in rhino, take 5 TH/SS termies with chaplain in LR, give your scouts snipes and ML and use them to camp on objectives in or near your deploy zone, if you want use CC scouts good way is to put them into LSS. Instead of 1 vene dread take 2x rifle dreads(TL AC).
This, plus
Tac squads should probably just stick to
ML. Not really worth upgrading. To make them effective you really need a matched combi to the special weapon. This will double their effectiveness for 10 points. Duel Melta is generally your best bet.
The combat squad is a waste of time and points I'd dump it.
Dumping the assault squad means dumping the Chaplain take either a stock libby with Nullzzone and Avenger or Terminator armour
SS Libby with the same powers or Chaplain Cassius and in every instance ride them with the
TH/
SS Terminators.