For this year and next I would have to go with Sosa easily. He isnt that old yet.............., and its too unrealistic to measure one great year for a young player over more than several great years for one of the games better sluggers (cork theory aside..........., I really dont want to go there).
V. Wells is the real deal no questions asked though. In 2-3 years he should be out produceing Sosa. In todays blooming era of player longevity, no real telling how long Sosa can keep going though, as Sosa is still only 35 or 36. Even if Sosa emulates Bonds and keeps his power numbers unreal for a good many more years, I would think V.Wells speed and 5 tool #'s (speed!!!) should make him as valuable if not a little bit more.
"Son we would like to keep you around here but were trying to win a pennant this year."