Adding my opinion here.
I have almost a dozen character friends that were good people I encountered while pugging dungeons on the way to 60. Mostly tanks but a few DPS as well.
After running with them, it seems like they must have also added me because I would get tells from them asking if I wanted to do a ZF, or a BRD or a Scholo. I suppose having a healer on their list is probably as useful as having tanks on my list.
Once my buddy and I hit mid-50’s we joined a guild so that we wouldn’t have to do as many straight up pugs so now I have a big list of guildies that I’ll run stuff with and I almost never have to open the LFG channel since I have this network of friends and guildies now.
So for me, running instances hasn’t been like retail at all. One of the guys I met in a pug BRD even asked me if my guild was recruiting, so I shot him an invite and he has been a part of Spicy since our original guild merged with it. He and I were running more BRD on the weekend, finally got my Second Wind and off-hand from Thau!