Why dont you see more people using LT Blount with adv. homing Missiles? I realize its 20 points but it still seems like a good combo.

Only works at R2. Without reposition actions and action economy it's tough to force that to occur, and it's 20 points hiding behind 2/2/2 for defense.

Better Blount builds involve either thread tracers or deadeye + ion pulse missiles, since they're easier to get off and set up any fire following it.

Or ion pulse missiles

I use him in my ZEARC build with Shara Bey and Corran Horn. My opponents so far have been far more concerned with trying to focus on the Arc of the Ewing allowing Blount to flank and deliver his payload practicly unnoticed. He is then free to become a blocker or harass from the edges with lone wolf. I recently took down a tie build using him to critical damage Soontir Fel.