Nice analysis. Your conclusion matches my estimation pretty closely. The key point being that Mags will not likely top a 1.000 OPS and Polanco is really closer to a .340 OBP guy than a .380 one.

I think you might have overestimated Polaco and underestimated Guillen, though, which is a wash in the end. Does Guillen's age merit such a drop-off in his offensive numbers? When completely healthy his SLG hovers just over .500 and his OPS averages around .900 in his Tiger years. Yet, you have him dropping to the low .800's in OPS and mid .400's in SLG.