I’m sure someone has suggested this at some point but why not physical keys with an lcd underneath each key? This would allow those keys to be fully customizable and be worthy of the “Pro” designation.
Because it’s expensive, bulky, and unnecessary. Something like this already exists: the Optimus Maximus keyboard. And while it’s a cool concept, it’s not without its rough edges. [1]
I'm sure there's a prototype of this sitting around somewhere in Apple headquarters, either waiting for some patent to expire, or some key component to become cheap/thin/reliable enough.
