In contrast, on early Android 2 phones, I did the opposite -- increasing animation time to 2x. It felt smoother. I'd argue, that animation can cover unresponsiveness of application, and improve perception of performance.
Imagine moving a window 500px over 100ms in 30FPS, that is just 3 frames! It means your window will jump 166px per frame. On average resolution display this translates to a few centimers jump per frame. Not very smooth.