How should they do it? Here's my suggestion which I originally posted in a Pre thread in the lounge, but I thought would spawn an interesting discussion here.
On the 3GS, double-tap the home button and you go to all the running apps with live views instead of to the home screen. From there it acts just like Mobile Safari Pages, flip from app to app and press the X to close. That's where Palm nicked the idea of the cards anyway.
Only problem is that the home button double-tap is already used for going to phone favorites or the iPod, but since it is already configurable that way, why not add multitask management to that list of options? Making it somewhat optional also keeps the phone simple and battery life long for those who don't know any better while allowing experienced users the power of multitasking with the knowledge that their battery won't last as long. It's really the best of both worlds.
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