Well IMO task switching and closing useless tasks is one of the most important part in an OS. By the current design of android and iOS useless apps can leech battery as they please.

At leas iOS has a decent task manager if it's jailbroken: http://www.youtube.com/watch?v=YrGLGoB88So
As for android it's all a pain. Closing an app takes ages with all the menus submenus and long presses.