I don’t think Apple will fix this as this is not broken. The “delay” was broken in 10.3.3 and for whatever reason Apple is keeping the ticket open. (At least this is my opinion)This video is not terribly informative without knowing when you’re pressing the home button. An external camera with microphone near the home button would be better.
For the record I tried replicating your video. The delay is not present or very minimal when opening apps if you click to go home very quickly and before it’s zoomed to full-screen (actually about 3/4 full screen). Once the opening animation reaches 2/3-3/4 complete, the home button is delayed while the animation commits to opening fully, pauses, and then closes again. I believe you can see evidence of this in your video, but again knowing the precise timing of your button presses would be better.
Let me be clear however. I and I think others are not complaining about this particular use case. I’d prefer if no delay existed at all but I’m not terribly bothered because having to close an app so quickly after launching it is a rare action for me.
What does bother me is in general use when closing applications from the full-screen state, an action most of us perform dozens if not hundreds of times a day. In this case I expect the button to respond instantly as it did in iOS 10 and when it doesn’t the delay is even more noticeable and frustrating.
I believe there was evidence posted here that the delay, or animation speeds (or both) which contribute to the overall feeling of responsiveness or sluggishness is even worse on the iPhone 7 than the iPhone 8 for no logical reason whatsoever. The timings are completely artificial. I’m skeptical about Apple’s intentions here. They haven’t come out and given us a single good reason for the change.
I’m glad some or perhaps even most don’t notice it or care, but I do. It’s very annoying to me, to the point that I’d downgrade if I could even if that meant additional security threats. As someone who’s very security and privacy conscious that is telling about the degree to which it annoys me.
I’m going to visit the Apple shop tomorrow to do some testing of my own.
As far as this thread more time was “wasted” in this thread than probably the total of all seconds for all idevices users “wasted” waiting for the “alleged delayed” closing animation to complete. It’s ironic there is no time to wait .1 second for a closing animation but plenty of time to write a post that takes 60-240 seconds.