Zenith might be strong, situationally. If we burried that Zenith deep down in some terrain, built a wall and put some gausses on top of it, it would take SL a lot of time to cut through. Zenith's good terra is now what makes it currently strong.
Btw since all superweapons are now able to terra down terrain even if there are structures on top of it, perhaps it would be good if one was able to raise terrain that has already a structure on top of it with a constructor. It could be like three times more expensive than normal terraforming, but building a wall with razors on top of them, having them all get lowered down with a SL and not being able to raise the wall again after the enemy SL was destroyed (without removing all structures on top of it first) is kinda annoying.

Don't forget that Starlight can outrange Zenith, it makes a huge difference.

The normal laser uses cratering, only the craterpunch uses smoothing.