quick feedback.
generally, the heroes are great in early/midgame but in endgame, they're quite useless despite their weapon upgrades. reason being is that they mostly find a mec with the greatest armor and decide to zerg onto it doing 1 dmg each round (coz of armor) rather than shooting the weaker enemies first at least. since they don't have any survivability too, that makes them more or less non existant.
suggested solution is that you got 3 tiers already, so changing 2nd and 3rd tier. suggested 1st tier has 0 shred/shot, 2nd tier has 1 shred/shot (midgame), 3rd tier (lategame) has 2 shred/shot. that should solve that issue without making them much stronger.