Forget about his age and all that. I'm not saying we should or should not plan to get him. It's hypothetical. Right now the Suns have a better record is fighting hard every night no matter the opponent. Of course it's not just Nash getting it done, but he's a huge reason for it (imo, still the best PG in the league).
It's an interesting thing. First people said Stoudemire needed Nash, then Stoudemire showed he can have a lot of success without him and made people wonder if it was the other way around with him and Nash, or neither, and now, Nash is still doing his thing.