Haku

[fastrthnwind]

Haku IMO would have made it to become an elite jounin. If he had become hardened over the years and was willing to kill someone when necessary, he could have been near kage level.

The same could actually be said for all of the geniuses that Kishi has killed off.(Kimmimaro, Kidomaru, Neji, etc.)

 

[Kung Fro]

Oh how I wish Kimi and Haiku were further developed.