Do you believe an ESL teacher/instructor has to have a native or near-native accent and why? If so, what accent should that be?

Not native accent, but near native is Better cuz English as second language the target is well communication and friendly gesture. After the course the learner has alreasy aquired the ability to improve/adopt accent.

I personally don't think that "native" speakers have an accent, after all it is their language, regional dialect maybe but accent, no! I have had Americans say to me "I like your English accent", but that's the way I speak, I'm English. Pronunciation however should be as close as possible to that of a "native" speaker as it will sound "right" or "genuine"!