I wouldn't -- the number of times I've inadvertently hit C-w rather than C-s (or M-w when I wanted something else), or control-q when I meant to hit control-a, FAR outnumber (by two orders of magnitude) the number of times I've wanted to close windows or exit my application in that manner.

Perhaps it's my windows upbringing, rather than mac, but Ctrl-F4 / alt-F4 are my preferred window/app closers, and I wish dearly I could unmap the other shortcuts sometimes.