Probably an obscure, low priority feature request, but here it is:
iOS7/8 is too fancy to use the standard circular rounded rect for icons. Instead favors the "superellipse"
I thought it would be cool to have "superellipse" along with Round, Concave, Straight, Cutout corner styles available in the Rounded Rectangle tool. (but maybe its better as its own shape, rather than a corner type under rounded rect, I dunno.)
I did see a twitter post with the equation needed to make the proper corners to fit in on iOS 7.
https://twitter.com/marcedwards/status/347451374214213633
Thanks for your consideration.