yeah im sure mechs would be fun to fight against just like the current tank sponges all slashes with no sound reception or signs of damage
anyway mechs will inevitably face the same exact problem that tank does wherein its too cost effective skill wise to the vehicle and get gutted and put in a garbage bin;
marines already have the potential to be deadlier than a single xeno anyhow so its not like they worry about that type of balance on an individual scale for good players, alpha pvts maybe it applies
also "its in the lore" or comics or w/e has never been a good reason or backup to any argument and you all know it else we'd have old acid blood 70 burn among other shit mechanics