Actually I think second base is worse than SS. 2B seem to tend to age worse than SS, I think because it's harder to protect yourself on the double play when they are coming into you blind.
I remember when the Mets got Alomar and he tanked back in 02, I then looked it up; a lot of good second basemen had their last good year around 32 or 33. (Though I guess you could say that about a lot of players, huh?)
As far as historical goes, Cano has a ways to go but he certainly is looking like a HOF player. Joe Morgan to me is the best second basemen of all time. Joe Morgan in 1975-76 was probably about as good a baseball player as you can be (Jesus, I just looked up Cano's stats this year; I didn't realize he was having THIS good a year). I'm thinking in a few years he might get moved off the position, but the time doesn't seem to be now.