Honestly, it's not a bad idea. I do think Hayward is a slight bit more valuable than Green, so I might want some minor draft pick compensation coming back Boston's way, but Dray does offer more of what this team needs than what Gordy brings, who is mostly just a redundant piece on the Celtics.
Unfortunately, I don't see any way Dray and Jaylen Brown would get along. It's becoming rather apparent Brown is a bit of a turd and has a hard time dealing with other strong personalities. Dray is no peach either, so I'd be rather worried about the lockeroom chemistry.
But these are the types of trades we should be exploring. The fact that our 5 best players really can't share the court often enough (due to positional overlap) is an issue that will need to be confronted at some point.