Re: In retrospect, would you do a Ryan for a Guzman again??
While I would absolutely love to have Ryan back in the fold, I don't think you can really regret any trade which funtionally put you in the playoffs.
If you're asking if I'd trade a promising AA closer for a starter that would put us in the playoffs, the answer is yes. We had no way of knowing Ryan would turn in to the absolute monster he's become and we had Williamson and Graves both throwing great in the pen.
If we're in the hunt and we can trade say Ryan Wagner for a proven vet starter for the stretch run, I'd do it.
Games are won on run differential -- scoring more than your opponent. Runs are runs, scored or prevented they all count the same. Worry about scoring more and allowing fewer, not which positions contribute to which side of the equation or how "consistent" you are at your current level of performance.