Gatecrasher is an overall pretty solid mech, BUT its ability is not all that useful. More often than not, when attempting to hit people through walls with it, they move away from it, since the delay is often JUUUSSST long enough for someone to walk away from it without getting hurt. In addition, landing the ability on people is difficult, since the projectile is pretty slow and has no auto-aim. The damage however is actually pretty decent, and I don't think it needs to be changed, I think that gatecrasher just needs a projectile speed buff, and maybe to increase the width of the beam, that way it can better control and deny areas.