For one thing, the whole "exciting rebirth" was probably supposed to be sarcastic--given my previous post with May's death in #400, the general consensus was that everyone thought she should have stayed dead and bringing her back in the way that she was was poorly done.
I would argue that if you're discussing May's return from the dead, that the death of Baby May IS necessary--because right up until the big reveal, the readers (and Peter) were all lead to believe that "May is alive!" was in reference to Baby May, and not Aunt May.