Froyo 2.2 has a task killer built right into the Task Manager, so they obviously can't be that bad.
I think in that case SkullDragon, the OS designers realize that the
Market Place doesn't really have the Oversight and Quality Control
that say Apple imposes on any and all apps that get posted for
sale on iTunes.
Having said that, access to kill tasks has always been available
within the Android OS itself. But, if 2.2 allows you to one touch
kill something - They must have anticiapted that some poorly
coded (unstable) app might hijack system resources and be
difficult to close.
I am guessing here. My VM Intercept hasn't been upgraded
yet. So, I'm not speaking from any real experience. But maybe
someone that has upgraded would care to jump in and provide
more insight. Sorry if I'm off base here in either case.