You can definitely have local variables on the stack. I don't know where you got that you don't use the stack. Heap is kind of a no-no, although memory pools are used.

> If every variable has a fixed address, and one of those addresses goes bad, a patch can be loaded to move that address and the mission can continue.

You can and do put the stack and heap pool at fixed memory ranges, so you can always do this. I'm not sold at all with this reasoning.