It's possible they fixed the issue I'm talking about by 10.3.3. I turned off Reduce Motion after a few versions of iOS 10, since it didn't rectify the issue. I had waited over a YEAR for them to fix it, so I forgot about it. Glad it's working on later versions of iOS 10.The 7 did have a hiccup in the close app animation before 10.3 but the response was still instant.
I'm using a 7 on 10.3.3 still and I always have reduce motion on and I can interrupt animations by hitting home and so can my wife's 6 on 10.3.3 so I'm not sure what you are talking about.
However I did play with every iPhone except the 5S on iOS 11 yesterday at a store and I did notice you can hit app icons mid close animation like you used to be able to do on iOS 8.4.1 and below. That is a welcome change back! Maybe that's what you are talking about.
Another thing I noticed is how slow the iPhone 6S was to open the settings app. I cleared everything out of the app switcher and opening settings took literally 3 full seconds every time I opened it.
My wife's regular 6 on 10.3.3 felt faster side by side opening the basic apps compared to the 6S. Maybe something was wrong with it or it's just a worn out demo phone but it was weird.
The opening app animation just feels slower on all iOS 11 devices compared to my 7 on 10.3.3 and of course the delay on the 8 when closing apps still super cringeworthy. Also the delay entering multitasking is there too compared to iOS 10. Just an extra half second till the multitasking opens after a double click. Still trying to figure out why they'd slow this down.
Either way, Apple fixed it. It took forever to fix it, but they did. I have no idea what took them so long to fix a minor animation bug, so that's anyone's guess.
The point is that there is a correlation between the Reduce Motion issue and this new "home button" animation issue. Since iOS 9, there has been an issues with home button input:
iOS 9: Reduce Motion input delay
iOS 10: iPhone 7 Home Animation glitch
iOS 11: Universal Home Button delay
The real question is: Why does Apple change the animation of the springboard every year? Every year over the past few years has had issues related to it.