Take a look at major league players. There aren't many who didn't have a breakout season by Stubbs' age. Torii Hunter is a notable exception. He was a fairly bad hitter in the minors until he was 24. Generally speaking, if you want a guy to be an .800+ OPS player with any regularity in the majors (and that is absolutely what you need from a CF), then you generally are looking out for players who've hit for .900+ OPSes somewhere on their rise up the ladder.
Yet there's likely going to come a time when Stubbs can't carry those meager stats up to the next level and then his value becomes minimal. Chances are he's either going to make a big jump in his plate skills at some point or fade away. You really don't see players that are able to maintain their game at just good enough.