I bought an iPad Pro (12.9") in mid 2017, and am already seeing significant slowdown. With 4-5 apps open, it lags when trying to scroll the home screen. I frequently need to kill open apps by going into the app switcher. When I bought a new iPhone, the difference was night and day. I regularly leave 30+ apps open without worrying about lag. Not sure why the iPad Pro struggles so much with multitasking, but it's kind…
This doesn't help most of the time.