Re: AAA Age Question
Personally, I think by 25 a legit prospect should be ready to contribute in MLB and pretty much avoid AAA from then on. That's my rule of thumb, which I've only stolen from the sense I get from publications and posters.
Stars fade fast after 25 because it indicates they lack something to contribute throughout their prime years. If they're good enough, you'd like them to be by 25 so they can give you their best years blended with experience.
Often times a player will hatch later than 25 (Nelson Cruz), but in general it's a good number to look at. There's no reason to cut a guy based on age if he's still helping the club in AAA though.
If you're looking for solid progress, 23 years old as a AAA player is decent, with a September call up to boot. Think Joey Votto or Francisco.