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.
You need very high frame rate to make fast animations feel smooth and natural. I suppose older Android phones had quite low frame rate and required slow animations to feel smooth.
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.
