I like the animations. But the animations in earlier versions of iOS took too long. I think part of it was to hide delays, but part of it was just a design choice. As people got more used to these phones, people wanted more snappy transitions, and Apple obliged, knowing their faster SoCs could handle it.
My wife keeps saying that iOS 10 is faster than iOS 9 on her iPhone 6s. To my eye it isn't (except maybe in Safari), but the animations are indeed significantly shorter, making it seem faster at times. But, it still lags and stutters occasionally here and there (something she doesn't really notice). The experience on the 5S is similar. Animations are shorter so it sometimes makes it feel sped up, bit it really isn't (except maybe in Safari) and it still lags and stutters here and there.