[lloeki]

1) no battery will be consumed by "runaway loops" because it will either be closed or be completely frozen in the background, regardless of the app design and epoch (pre- or post-multitasking)

To perform computations in the background, an iOS app has to be voluntarily coded to do so by using the multitasking API.

(3) half a gig on the iP4 is plenty enough to hold numerous Safari tabs, a huge game like Infinity Blade or Dead Space, and half a dozen random apps (twitter, messages, mail...).

[Stormbringer]

I can confirm that (1) is in fact wrong. I have apps that when I run them and then 'exit' the battery gets chewed noticeably faster.

Half a dozen apps is not very many apps. In fact, it is a ridiculously small number of apps for a device that is "all about the apps".

[lloeki]

Which ones? I'm curious, it would be interesting to know about them so as to avoid such buggy bastards who dare to resist to SIGSTOP (or its equivalent).

The task switcher is not a task bar, it's a MRU list. You're better off finding them again on Springboard if they're not in the half-dozen most recent apps range, which is muscle-memory. What do you expect? you can only fit so much on a ~3" screen and make items touchable. Stuffing more icons would make the task switcher end up looking like Springboard anyway, only messy because you'd have to scan through it due to the number of items. Springboard + muscle-memory beats that anytime.