The Saviors will fall apart if Negan dies. When Negan dies. They won't self organize after he's gone, lots of dudes will be looking for that empty seat, it'll create a power vacuum and they'll be vulnerable.
I guess Dwight decided to set that guy free... Must have gotten through to him. Sort of.
It's a big world and there were definitely other places to go. They both could have just ran...
It would be grand if Daryl killed Negan and went down in a blaze of glory...
He could totally do it. If he just plays along long enough, he'll get a chance...