Why would you think that making a potential paying customer unhappy is intentional? People likely get to that point before their subscription starts and the subscription is where the real money is.

Healers are the big "restriction" in pre-30 dungeons because there is only Conjurer at that level, it gets a bit more balanced post-30 where Scholar is able to join the queue.

There is supposed to be a looking for group board to allow people to post requests for party members for whatever content they want so people can look at the board and see who needs help with something. There is also going to be a Random Duty Finder function where you must queue solo and you get stuck in a random Duty that you've cleared and receive a reward upon completion. That, along with the new MVP system (if it has some good rewards or bragging rights) will hopefully get more people helping out newbies.

Hopefully they will boost dungeon XP though...