Amiga's pointer was a hardware sprite, so that always stayed responsive. Was more thinking of the OS's themselves rather than within applications. You could certainly get Amiga to slow down in the apps, particularly if you were programming it badly. As it generally only redrew when needed and managed layers and viewports pretty well, getting it that laggy would have taken effort. :)

Took years after I abandoned the platform for serious use for Windows not to always be more sluggish, and get dramatically worse when under load. Course by then I was on '040 comparing with Pentium something.