AbdulAlhazred
Legend
How often is it that you can end up killing a foe with that free attack before he kills you? Seems extremely rare, to the extent that even if I allowed it, the chances of such a scenario coming up would be extremely rare.
Or is there something I am overlooking?
Forced movement or other conditions are the common cases. Its fairly trivial to build a martial character that can sub in a power for the MBA or use one of any number of feats to make it possible to push an opponent with an MBA, or use some item which can do it. It certainly isn't sure-fire as it will require a crit or use of a restricted resource in most cases, but surely if the character was going to go down it would be worth it. Even if the attack wasn't negated entirely a condition could be applied that caused it to miss or reduced damage. I think the idea is these kinds of things are just outside of at least the RAI of a single feat.