It was well-publicized that the point of "Avengers Prime" was to transition Iron Man, Captain America, and Thor back into being friends again. By issue #4 (of 5), the moves made towards that status quo are definitely becoming visible, but, at the same time, Bendis is turning in the most traditional Avengers story he's produced in his long stint as writer. That's not just because of the cast, the team's "Big Three."
It certainly helps that Bendis has a reasonably good handle on the characters, although it does jar that his portrayal of both Thor and Iron Man is wildly different to Fraction's in both cases - and occasionally, actively ill-judged. Stark was never particularly strait-laced, but in the absence of Spider-Man he seems to act as Bendis' comedic mouthpiece, and for a story that's supposed to bring Thor, Stark and Rogers together, the audience should be rooting for that to happen, and not getting irritated by any of their portrayals.
However, that's mainly just a bit of inter-title nitpicking. Taken as a stand-alone Avengers story, the issue (and miniseries in general) is working really well, with big-scale plotting juxtaposed against personal interactions. Given that one of Bendis' most frequent mistakes on "New Avengers" was substituting plot for story, it's nice to see him write something with a clear central theme as well as a succession of escalating action set pieces. The invocation of some of the more epic elements and artifacts of Asgardian lore make this almost like the classic 60s or 70s-era Avengers, and in a good way.
Ultimately, though, the real draw of Avengers Prime (if you'll excuse the pun) is Alan Davis, whose clean figures and nuanced storytelling perhaps serve to temper Bendis' excesses somewhat. It's still recognizably a Brian Bendis comic, but Davis' pencils give it the veneer of something more traditional, while bringing their own flavor to the work. There are few superhero artists who can cope with fantasy settings and make it mesh, but here, Davis manages it splendidly.
With "Avengers Prime" firmly settled into its groove, there's little else to do except acknowledge that this issue, as the penultimate issue of a miniseries, can't really be criticized for failing to provide much in the way of twists and reinvention. There's more to come, and as we prepare for the final act, what sticks out most is that it's a book being created to high standards. A must-buy for Avengers fans, and a refreshing change of pace from Bendis' usual approach to the team.