I've never had a problem as a tank in low level dungeons, and tanking is my secondary role. Let me tell you , my tanking skills were wretched to start, but very few low level dungeons are so unforgiving that a stray mob will immediately wipe the party if you actively try to get it back and try holding hate. A healer will be able to correct these mistakes easily, and anyone who complains about a player honestly trying and honestly struggling is complaining for the sake of complaining, especially if they aren't offering advice.

More on topic, Main Story roulette is condensing all leveling dungeons from ARR and HW into a large pool of dungeons, which will help populate lower level dungeons with higher level players, and the new jobs start at level 30, which will put them in the first 5 dungeons right from the get go.