I'm not a fan of the plasma pistol. A Combi-Melta is more useful. I don't... it depends a bit on the state of the meta.
For an ultra annoying set-up try to give the MOTF the Conversion Beamer and attach him to the Scouts (giving him ablative wounds) in a bolstered ruin. As long as you keep the ehemy away from him, they'll wreck MCs. Or if tank hunting, just rely on the cover without the scouts attached, freeing the Scouts for other stuff..
Worse your Tac Squad clocks in at 130, you are 10 too high. You can drop the Plasma Pistol and Power Fist for a Scout ML and Melta Bombs on the Sarge.
Have you ever run your list against a horde army? (Granted they are difficult at 750 anyway.)
I'd consider dropping the lascannon on the dreadnought (in favor of sth more useful against hordes) and give the MOTF the Conversion Beamer. How about dropping back to TL assault cannon? The only drawback is range.
Alex