I'm not sure that I understand why you don't like it. It seems easier to just have the function on the home button, then you don't have to look where to tap on the screen, just move your thumb over and push the button.
Well, that's not how the iPad works unfortunately. You only have one program available to you at any given time.
Not the Gods, the "Jobs." Steve Jobs.
Not understanding what a minimize button would do. iOS doesn't have windows to minimize. Double-touching the Home button brings up the tasks list so no need for another button to get there.
No need to do a "kill all" on an iOS device. This isn't Android after all. Go into an Apple store and test drive one of their display iPads. Those things have run every app on them while people play with them. Performance doesn't suffer.