I agree with the part about Kepler needing more seasoning, but not with calling Kepler a "tweener," or at least not the connotations of calling him a tweener (i.e., that he can't be a good corner outfielder unless he develops significantly more power). Even if his power develops only a little more, he's a tweener only in the same way Alex Gordon is a tweener. I'm not saying Kepler is going to be as good as Gordon, just that he seems like a similar profile player. Kepler can hit only 15 HR a year if, like Gordon, he has a high OBP, hits some 3B (Kepler would probably hit more) and a lot of 2B, has very good D, and steals a few bases. With that skill set he can still be an above average player, and depending on how good the D, how many 3B and 2B, and how high the OBP, even a really good player. HR are great, but they really aren't necessary if the value is provided elsewhere. Gordon averaged fewer than 18 HR the last 5 years but has been worth 27 WAR in that period. If Kepler is worth even half that WAR the next five years, he'll have been a valuable addition. I think that's quite possible even without developing much more power.