Sorry @Angad but I don’t see how keeping buttons shape and shadow as is would stand in the way of new features such as icons and text sizes.
Btw the former you could sorta do with emoji or images in button label, and the latter you could do with this trick.
This also broke many tailor-fitted docs where we now have to go over all of them and resize button columns.
All in all, I’d love some choice. Akin to serif vs sans-serif font in the page settings I want a choice of flat&round vs squared&elevated. My complaint is more with how unexpectedly this was rolled out.