@trifid @imagineadam
This issue still occurs in 9.3 beta 3. Apps do load faster it seems but the input delay the same.
Thanks for assembling the list in the OP ( in the link below) on where it occurs and where it doesn't. I found that useful but unfortunately now the thread is closed.
https://forums.macrumors.com/threads/ios-9-vs-ios-8-4-1-unresponsiveness.1942001/
Hey man thanks for following up. I hope that thread gets unlocked and hopefully it'll go back to the original topic of input-blocking which is what I care most about since it seems the stuttering issue has gotten a decent improvement in 9.3 (still not perfect).
If not, I'll probably wait for iOS10 to evaluate if there is more severe input-blocking introduced or if it's been fixed, to open a comprehensive input-blocking thread. At least it'll serve to document iOS's weaknesses and to link to Apple on bug reports.