Thanks for taking the time to look into these!
Switching brush - is it available in any other painting app?
Not that I've seen. Maybe the Brush Preview Box (or a modified version), would be clearer than the cursor since it would be onscreen for a short time and has more opacity.
Resizing brush cursor - we will consider adding option where it will be shown
Note: I've found that if I set Finger Function to adjust brush size in preferences, the cursor follows the finger (like I suggested), but if 'Three Finger Swipe' is set to adjust brush size, the cursor stays in the last position the stylus was at. While I prefer the cursor to follow the movement of my fingers, I can see that some may prefer it to be stationary. So, I'm just asking if cursor follow/not follow (and possibly Brush Preview Box visible/not visible) during resize could be made an independent option rather than be tied to the one finger or three finger gestures.
Cursor when resizing - rather not, there is already "brush preview box" which shows the same.
This idea is somewhat related to the previous suggestion, but I understand that setting cursor = none is sort of its own mode.