Failure to get on base. Until Revere can consistently hit above .300 and OBP at .340 or better, his value is marginal. Guys who are threats on the basepaths are only useful if they can get on base. Revere did that for half a season but the other half, he failed to get on base often enough to be a legitimate MLB starter. But, as you said, he's only 24. There is room for improvement, I just don't think he'll be the player some Twins fans dream he will be. Disclaimer: I'm almost always down on burners who can't hit it in the gaps and can't take a walk. Without those attributes, I don't care how fast they are, they almost never turn out to be much better than league average.