One could simply have 2 fire modes direct and indirect.
Direct fires AP rounds to low range indirect fires HE.
Instead of suppression I suggest "shell shock" a critical that reduces the DPS of the unit affected. (same goes for ST).
Direct hit could cause vehicles critical like driver injured gunner injured instead.
The unit then could have utility instead of raw fire power.
This is a pretty good idea. No one wants the one-shotting B4 back and adding utility would be a good workaround.