1) David Lee is awful. There are not many teams that he would be helpful to at this point in his career.
2) Iggy is still a good defender. But he's no longer in the leagues top tier.
3) Klay Thompson is a good defender but Harden lit him up the last two games. Probably says more about Harden than Thompson though.
4) Draymond Green is universally acknowledged as one of the top defenders in the league.
5) You underrate Steve Kerr as a coach. This GS team changed very few players from last year. The difference is Steve Kerr.