Well, it's definatly more challenging, but I wouldn't say raiding is multibox unfriendly. Maybe most guilds and acceptance of multiboxing is unfriendly, but not game mechanics.

But I disagree with saying it is multiboxing unfriendly. Having done all ten man content uncluding Sartharion with 2 drakes up. Working on 3 drakes, >In a casual guild!< At all times with at least 3 of my characters present. I'd say raiding is very multibox friendly.

But jsut adds more layers and makes it all more challenging, and ore fun. More fun to me means it is more raiding friendly. :P