I do agree about Vermaelen, he's club captain yet isn't getting a game at the moment. Koscielny is a top defender who has shown he can keep anyone in his pocket (though is prone to rash tackles), and Mertersacker is fantastic alongside him and compliments him well, Vermaelen seems to realise this, and if anything it seems he'd be of more use retrained as a backup DMC than anything else. Though at his age it is perhaps a little much to ask considering the competition in midfield.
I think the problem with defensively minded players, is that Wenger's tactics focus on forward thinking players with plenty of vision. You want the opposition on their back feet, marking your players instead of moving to find space yourself. The way Wenger wants the team to defend is with pressure, similar to Barca.. force the defenders into cocking up, win the ball back, and then focus on passing it through their lines. This has caused problems in the past due to the incompetence of centre backs and general defensive frailties, but it seems a lot more stable at the moment.
Flamini is massively effective at short passes, breaking up play and anticipating those balls, the same as Arteta - but the top possession sides need that DMC who just plays it simply, and is physical enough to not get bullied whilst also having no problems in possession. Flamini seems to be doing the 'Busquets' role at the moment, simple passes, bringing in his more talented teammates, and stabalising the defence .. Arteta does this a bit differently, but this unfortunately leaves him vulnerable to having a man on him, which is why high energy CFs/CAMs give him problems, see Rooney or Oscar.