It's not the first time the gain changed between firmwares. Yes maybe now it's too high to be realistic (compared with the actual amp with the exact same setting), in which case this question is completely valid. Is the gain higher than on the III with a simple preset of the same settings? Then too it's valid.
With this firmware I suddenly like amps I never liked before, e.g. the AC30 and the Rectifiers. Do I like them now because they don't sound realistic anymore, but went into a direction of my liking? I doubt it for the Rectifiers, because I owned one before I switched to the Ultra. It's the first time I like it in the Axe without the need of a boost pedal in front, which I never did back in the day with the real one. The AC30 Hot now can almost be used as a metal amp. Does this make sense?!
This update is obviously a big one and I'm pretty sure the raise of gain is kind of a side effect. If you don't like it, lower it again, just as we did before with other firmwares. If however this is based on a bug, then it should be fixed!