Actually, it seems ok, but as Stelek said, beef up the assault squad, and remember, why take a missile launcher when you can get a
HB or Las? Las kills tanks better,
HB kills inf better. Missile launcher with marines just isn't worth it. Also, for
tac squads 6 men is the unofficial minimum. Kit them out with meltagun and multimelta and have them hunt tanks. Also,
HB sponsons should be taken on a Destructor. You don't need that pred actually. Venerable Dreds look good, but you should consider switching in the
SB's for Heavy Flamers. More hits, higher strength

and with the current kit on those dreds they are tailor made for taking on infantry without fists in
CC.