I really did like when keys could deplete. I think the quality of 5 man players was higher overall back then because not so many people were doing it, one, and two they weren't really doing it to gear their character per say.
A lot of people who were afraid to do keys before 8.3 are dipping their toes in now, there's nothing stopping them. Most of the healers in my guild just stopped playing, but Blizzard is to blame for that for allowing Shamans to be so shitty at healing and for allowing Paladins to be so one-dimensional at healing in 5 mans (class design incompetence).
TL;DR: healers need to be buffed in 5 mans in terms of heal toolkit and design.