They fixed the swimming pitch up/down problems. Originally if you swam to the surface or simply entered water your pitch would zero out, prior to the last patch this wasn't true. I was constantly entering water and starting a dive. Swimming to the surface wouldn't reset it. That is now fixed.

Also I always thought that mounting your flyer should reset your pitch (it didn't use to) but it seems that has been corrected. Although I haven't done enough testing to verify this.

I always hated it when mouse driving around I'd stop to mount the flyer, jump up and imediately fly into the ground or into a pack of mobs (when using the keyboard to fly). I always had to jump up and then land again to reset the pitch.