How many Warriors games have you seen over the last couple of years? Green is the heart of that team, he's also their primary playmaker on offense, and their best defender. Doing all of that allowed Steph, Klay, and KD to concentrate on scoring. KD's gone but that just means they'll need Green to step it up a bit more.
There was talk of the Warriors having to choose between KD or Draymond this offseason when they were feuding early in the season. That idea isn't even discussed if Draymond was just their Rodman.
Comparing him to Rodman is ridiculous. Rodman was a great piece for the Bulls but the Bulls proved they could win championships without him, he just made the path easier. Green is much more the Pippen of Warriors than Rodman. He often guards the opposing teams best player, handles the ball a lot, and is relied on to get the offense going when Steph's having trouble getting it going. Green isn't asked to score in place of Steph but he is asked to get buckets somehow, and he usually does that by finding the open man for an easy basket.
You don't have to like Green, most people don't, but to discount what he does for the Warriors only shows that you haven't watched many Warriors games. I'd say he's overpaid if he got that much from another team but to the Warriors, that's what he's worth, perhaps even more.