I think anyone that cares about improving the Celtics says no.
I very much care about improving the Celtics and would reply with an emphatic yes to that hypothetical trade 
Yeah maybe three years ago.
Have you watched Draymond the last couple of years? He's not even close to the same player he once was.
And my goodness, do Celtics fans underrate Hayward, who is legions better than Green at this stage.
This wouldn't even be a discussion three years ago.
Have you watched Draymond in that 2016 season? He was a top 10 player that year with his DPOY level defence combined with excellent big man passing and efficient mid-high volume 3 point shooting. He's dropped off quite a bit the past couple of years, but his defence and passing have largely remained intact, which still makes him a very valuable player whose skillset scales higher and higher up the more talented his teammates are.
And my goodness, do Celtics fans overrate Hayward, who's still an inferior player to Green even at this stage.
Come on man now you're exaggerating.

Draymond was always a product of his environment. Placed in the middle of a superb team and he shines. Put him at the helm of a bad team, and he’s elite at nothing. He’s a fine player I suppose, but would never be an all-star if not for being surrounded by two all-time-great shooters.
My sentiments exactly. He's a multiplicative player - he makes good players better, but by himself he's not anything special.
But what makes players valuable is their ability to provide championship equity - a run of the mill floor raiser is not more valuable than a great ceiling raiser who struggles to lift poor teams like Draymond. Obviously Hayward is a decent floor
and ceiling raiser, but even a banged up, non-shooting Draymond gives an already good offensive team quite a bit more additional value compared to Hayward. I certainly don't think the gap is huge like 2016 Draymond to 2016 Hayward, but there's still a small gap between them in terms of quality, and I'm pretty sure that this isn't a super wild take if you ask fans of other teams around the league.