Great post, Kriston! That covered most of the drawbacks that I can think of.
Just in our personal experience, dd#1 helped teach the other students in 4th grade math and I wouldn't do it again. She probably did a decent job of it and enjoyed the accolades and responsibility, but there were drawbacks. Primarily, she didn't learn much of anything herself and she also wound up with other kids looking up to her and treating her like some kind of idol.
At student presentation nights where the kids presented work they had been doing at school to their parents, other kids read off dedications wherein they went on and on about what an inspiration dd was. It was nice for her self image and it was nice that the kids at the school she was attending at the time didn't pick on the bright kids, but rather admired them, but it wouldn't have been a good thing in the long run for her to get the idea that she was some sort of superior being whose age peers would treat her like that.
She's had a bit more of a reality check in middle school: she is smart, but she isn't going to be idolized by everyone.
