I actually had the same thought—it felt like they bumped Asuna by at least one cup size. Not that I was looking. *cough* At all.
I don’t know man… I’m probably one of the few who enjoyed the Asuna fanservice. lol If I let every little fanservice in SAO get to me, I probably would have a hard time watching the anime. No matter how much we complain, it will not change the fact that fanservice was added. Also, melons always look bigger when no clothes are covering them (not to mention the position she was in).
The studio making this season is the same one as the previous season (A-1 Pictures). Well I guess they felt bad that all the fanservice went to Sinon so they decided to add in an anime original scene of Asuna bathing. I don’t think they really messed with her size though. It looks about right to me. I guess you were just not used to see a full body fanservice of her since she’s usually covered in amour?
Meh, I suggest to try and ignore or just accept the fanservice if you want to enjoy the anime. If not, it’s better to stick with the light novels. I personally can accept to a certain extend the fanservice they throw at us as long as they don’t ruin serious moments like how they did in Phantom Bullet. I still have hope for a good Mother’s Rosario adaption, although not a lot.