Haven't noticed it either, on Safari.

Good place to ask though, anyone want the default text box sizes increased? I figure I can keep the quick reply one here at the bottom small, and then make the full screen reply one larger. I'm so used to Safari allowing resizing I don't personally think much about defaults anymore.

And my perspective may be warped a bit now, since I tend to stare at 2560x1440 monitors most of the time now, could be massive already for some people.