Most of this comes down to more of a subset of users that have learned to ignore or brush off things with Apples software. It isn't some weird coincidence that many on this thread can reproduce the lock screen wake delay and stuttering home screen lag and unresponsivness when exiting the music app on a range of devices. The one constant I've notice is the issues don't happen until you've been using the app for up to a few hours.
Let's keep on topic so that other can contribute. As of right now 8.4.1 beta 2 supposedly doesn't fix the slow wake on iPads.
Emailed Craig Federighi. He's replied to me before so I'll see if he responds again.