haas, every study I've ever seen indicates that at age 27 you START your prime. It lasts for a few years (31 or 32 I believe).
As for your list of teams and their 2B options, nice collection of assumptions. I stated this in another thread, but it applies here: There's no particular skill involved in coming up with excuses for what you can't do, a smart team figures out what it can do.
Players more expensive than Todd Walker will be traded this offseason for decent returns. Players less talented than Todd Walker will be traded this offseason for decent returns. Players both more expensive and less talented than Todd Walker will be traded this offseason for decent returns. Bet your life on it. Happens every year.
The Reds managed to get almost nothing for Todd Walker. Make excuses for it until the cows come home. This trade in and of itself does not help the Reds and, that being the case, Bowden had nothing to lose by waiting for a better deal to materialize.
And if the Red Sox (a team with an exceedingly thin minor league system) manages to package Todd Walker and some B and C prospects for Sean Burroughs then this trade takes a turn from bad to hideous.