You can but you shouldn't. The reason is 30pts. For a single shooting phase a CombiP is just as effective for 5pts. And I dont think your opponent will allow such a dangerous and expensive squad to live very long at 12". Besides, you lose range and your special ammo, but gain one whole attack in
CC!
and as i already run a plasma heavy army, i figured more plasma is the future.
Well plasma is pretty versitile ,but what happens if you face something you cant kill with plasma alone? You put on your sadface and wait for two hours? Your army needs ALL tools to deal with ANYTHING to have challengeing(=fun in my book) games for both you and your opponent.
No, dont be stupid. The heavy or special weapons all have uses too, it all depends on what role you want the unit to play. This squad can adapt to just about any role you devise for them (but at a price). From Melta hunters, to cover busters, to mini-Devastators, or even multiple roles at the same time.