I'll say Bob Harras. Usually when people reference his run, they're just cursing those damned team jackets. But I really liked what that run had going on. The Brethren, Operation: Galactic Storm: the Gatherers. There was a nice variety of big threats, but the whole run was also grounded really well in what was going on in the lives of the characters with the Sersi/Black Knight/Crystal/Quicksilver love... trapezoid and other things. I liked that it had an unconventional Avengers lineup too without it not feeling like the Avengers still. There was also a sense of professionalism to how Harras wrote the team. It wasn't just big battles and drama. You regularly saw them doing the grunt work of organizing, investigating and sorting out tactics. He covered all the bases and made the team seem very three dimensional. ...Note: I didn't read it all the way into the Crossing, so I don't count anything about it in what I'm saying. I stopped reading shortly after Black Knight and Sersi left. 
 
And you know what? I'll say Brian Michael Bendis too. I may not be down with every little thing he's done, but I generally have really enjoyed what he's done with the Avengers. He puts a lot of focus on the characters, which I like. Okay, not all of the characters. He does tend to focus on a few at a time, but honestly, that's more than I've seen a lot of other writers do with team books. I like how he has elevated Luke Cage and Spider-Woman. He brought Mockingbird back and made me care that he did. The character arc he did with Ares was awesome. I'm probably more invested and interested in his Avengers run than I have been about any other writer's Avengers run in the past.

I really loved the Red Zone arc by Geoff Johns, and Bendis because of Dissassembled, and New Avengers

@Enzeru said:

Not Bendis.

This.