Just upgraded from Yosemite to Sierra and the following started happening, so not sure if this is a known issue.
I use 3 finger swipe to move between spaces, and 4 fingers for mission control grid. In Yosemite, the transition between spaces was almost immediate after the 3 finger swipe. In Sierra, there is a delay of around 1 sec before the transition happens. Sometimes, the 3 finger swipe has no effect at all, and I have to do it several times before it finally works (again, after a delay).
My best guess: the 3 finger swipe is initially being interpreted as a 2-finger scroll by the OS. If I move the 3 fingers very slowly, the active window will start to scroll, and then after enough time it will change spaces. If I do a quick 3 finger swipe and it works, the active window will still scroll a tiny bit in that direction during the delay before the space actually changes.
Thank you in advance for any help, and let me know if there is any additional information/clarification I can provide.