From a pure time commitment aspect. I recommend playing SMN for all the story quests and swtich to Scholar for the dungeons and duties.
Dungeon XP is better than anything you can do in the open world.
There are a few spots alone the story quest where you will run out of quests to do and still be to low a level for the next story quest.
DPS queues as you have seen (being ACN to start) take significantly longer. As a scholar you will queue within a minute most of the time.