It’s pretty easy to swap classes. I suggest skimming over rotation/talent guides as you play a new class. Or you can wait until max, doesn’t matter a bunch while leveling.
IMO the game gets stale if you stick with one main for that long. I switch every patch it feels like. Maybe I’m an outlier, but brings a lot to the game.
Also it makes you godly at pvp when you know what to expect from every class.
You don’t need old reps or anything for current content. I usually grind stuff like that separately based on my goals [usually profession based].
Methinks you should just pull the trigger and go hamf on a new class.