im talking about the personality of player base, not preferred dungeons
These are two totally separate issues and we must be careful in trying to relate them. Does assembling a specific team equal bad personality? Not at all. There are many valid reasons for restricting the team composition.
So we are left with two separate questions:
1. Have meta team builds replaced the ability of a regular pugger to find a dungeon group? My experience says no. I pug 99.5% of my dungeon runs. I pugged my way to Dungeon Master. I do random pugs in FotM regularly. In over a thousand runs, I have never been kicked from a group.
2. Is the personality of dungeon runners bad? You'll find jerks anywhere in the game. Actually, I have found fewer in the organized teams than in random pugs. I can remember only one occasion where someone was setting up a CoF speed-farm group and being a jerk about it.
By setting a minimum bar to entry you eliminate the players who don't care enough to work hard for something. When I first started running CoF, I didn't have the gear or skills to run at the level I do now, so I invested time and effort to getting what I needed. Now I run with pro groups.
Profession restriction has no definite link to the personality of a player or group. If you want to run with the designed teams, meet the requirements and they will be happy to have you; the majority are quite friendly. If you can't be bothered to put in the effort to meet the requirements, there are plenty of random pugs that run dungeons perfectly well.