Looks like you’ve already gotten a lot of good info on potential perks of leveling another class, so I won’t add anything there.
If you do choose to level another class, I’d suggest doing the Hunting Logs for it! This is the fastest way to get early experience to get classes up to the level where you can start doing daily roulettes. These are available for all base-game classes and can be found under the “Logs” menu.