Woah, I just used the iPad annotations for the first time in a few months and the improvements are great! Thank you! It finally feels like I'm living the electronic notepad dream that has been part of product demos for a couple decades but never seemed to be realized in practice. So many elegant UI choices.

There is a small feature in another app (ZoomNotes, probably others) that I think is brilliant that I would like to suggest: the size of the eraser change dynamically with how fast you're moving the stylus. When you move it fast, the eraser is big for clearing large areas, and when you move it slow it becomes smaller for erasing small details. It is amazingly intuitive and completely removes the need for manually changing the eraser size. (The ZoomNotes developer is also very friendly, so he might give you some tips for getting it set-up correctly.)

Alternatively, one could use the tilt sensor to change the size of the eraser with the tilt of the stylus (I think Apple notes has this?), but it's not as good imo.

(Please let me know if I should put this in a new thread. Didn't know if that would create too much clutter.)