I continue to hope that 5.5 will move to "short rests are 5 minutes, but limited to prof bonus short rests per day."In 5e, it's a bug. The differing recovery mechanisms for powers means that class balance, in as much as it exists at all, depends on having 6-8 encounters per day. But the game does nothing to discourage the main spellcasters from blowing through all their big powers, overshadowing everyone else in 1-2 encounters, and then forcing a rest on the others.
If they do indeed move to "PB times per day" for all powers in 5.5e then it will become a feature. I don't think that would be an improvement, but YMMV.
It's a very simple change and works amazingly.