Even easier would be something that recognized that 00, 15, 30, 45 are going to cover most uses and thus made it a single tap to select which one of those you want (with the "more general please" option if you need it).
Excellent idea. What's great about Android is that I can clone the git repo, add this feature, and see if I like it. Much better than waiting for some "expert" to "decide" that this is best and then waiting for the next OS upgrade!