It's been quite a while since I've run the leve circuit to power level a class, so when I went to round an alt's Miner up to 50 I was a bit irritated to find I couldn't do the ones in Moar Donuts because I didn't have a combat class at 45.

Since leves cater to every discipline why are they locked behind combat classes? Why couldn't I do a lvl 45 Miner leve to unlock them? It seems like an unnesessary barrier for entry.