Yeah, the current infantry rules are notoriously scuffed. In A Time of War (where infantry weapons naturally get more love from the rules) standard Support Machine Gun can wipe over half a squad with one Suppression Fire Attack with a long range equivalent to over 8 TW hexes, but can't do jack squat against BattleMech armor without a magic roll of 10+ MoS. Meanwhile, in Total Warfare, Support Machine Guns vary from being a slight nuisance to infantry (if you only have one per-squad) to a rampaging inferno of death (if you have two per-squad), while also contributing a solid amount of damage vs. BattleMech armor, their only drawback being a reduced long range to six hexes. And that's not even getting into how burst weapons and underslung grenade launchers are factored into the equation. Oh, and range calculations make sniper rifles entirely useless (and before you point at Shrapnel snipers, I consider those outliers as their design principles clearly strayed from established AToW stat patterns as a workaround to make them useful in TW).
I've had some fixes cooking, but those don't belong in this thread.
On another note: Campaign or Tactical-scale combat? Yes, medics, all the medics, love my medics, God bless those medicinal maniacs and their MedTech rolls. TW-scale one-off skirmish? Nah, don't bother.