Tacs are lackluster for there price+pop cost+tax that incurs.
If heavy armor was actually resistant to suspression so tacs wernt instantly suspressed by everything they would be better.. banshees have 300 moral suspression resistance and no one complains about them(tacs have 100).
I just cant see Marines going "Take cover and cower, they have a heavy gun!!!"... Guardian squad.. even orks sure.. but tacs instantly cowering cause they were shot at while in heavy armor.
Units suspressed can refuse to fire at all once the suspression has worn off untill they are retreated.
Effects setup teams and long refire(such as scout snipers) the most.