With the irregular layout we have now, some keys are easy (e.g. C) and some are hard (e.g. B). If you make the layout regular, putting a black note between every white note, then every key becomes the same, but also quite hard, because every major scale is now played like this: https://i.imgur.com/6EmW8eU.gif

It's not a particularly good tradeoff. If you got rid of the black keys entirely instead, you'd have to remember which keys to skip. Harder for beginners than just playing in C.

There is the Janko keyboard though: http://en.wikipedia.org/wiki/Janko_keyboard