I'm burnt out as well, especially with all of the "ZOMG GOTTA PLAY ALL WEEKEND NO SLEEP!" beta times. I just hope that it doesn't transfer over to the actual game. Hopefully they have held back a lot of content, even pre 30. It was getting quite boring either running dungeons or doing leves constantly.
With the amount of quests available in the first 20 or so levels, I'm hopeful. I didn't mind dungeons so much, but Leves were kind of bleh for me. The main thing I'm looking forward to is having access to jobs finally.
As for getting burned out, I stopped playing yesterday afternoon and haven't been on it since. I already figured out what class I want to play–ARC–and how to go about maximizing my time. I'll skip most of the non-scenario quests and just focus on getting to 10 right away. That way, I can burn through the quests on CNJ instead. Other than that, Phase 4 can't come soon enough.