The only Zato change that really bothers me is the puddle being attack-able. I already struggle a lot with Zato's neutral, so it's kind of a kick in the gut to me.
It looks like they reduced his cooldown after Eddie dies unless it is prompted by -D-, and I think that's very fair, because Zato can set up endless unblockables right now against a cornered opponent, and that's just dumb.
Apparently, summoning from a puddle only takes up ~-P- worth of gauge, so it's close to a non-change to me.
I don't know how big the j.K hitbox change is.
I think that's all that was really big and harmful to Zato. But I wouldn't say that all of these changes are so small that they don't affect our play. The original loketest version of Zato would have set me back a lot.