Regardless of how fast you get to Max level, whether in a few days or a few months, it’s out levelling the quest content in relation to your story progression that’s the problem. Particularly if you do the side quests, bonus series and heroics. And if you want to do any of the other content like flashpoints, warzones or space combat then you will be over-levelled for the main quest line. For my play style, I particularly like to do all the quests (side quests, bonus series and heroics) in an area before moving forward to the next. I’m currently level 33 at the tail end of Tatooine with the next planet Alderaan starting at level 28. I agree with a gain experience toggle. Cheers