Neji? Oh don't get me started on Neji... Goddamn you Kishi. :devil:
Haku had a ton of potential, but he was too kind. Although like Choji he could probably outgrow it.
I guess Dosu had some potential, but Zaku and Kin definitely didn't.
Sakon and Ukon, Kidomaru, and Kimmimaro had potential to be Kage level IMO, Tayuya and Jirobo not so much.
Rin's abilities were never really touched on, but she definitely could take Obito XD
We never got to see Nawaki fight.
I think Kawarama and Itama could have been close to Tobirama and Hashirama's levels. Just based off their family.
IMO, this is how it goes:
Neji>=<Lee
Haku could've been low kage level. Stronger than Mei.
Dosu could've been a jonin, while Zaku and Kin are B-rank chunin.
The sound four could've all been High jonin, with Ukon+Sakon being able to fight a kage level ninja in a losing battle.
Kimimaro could've been Sanin level. He had a lot of potential. I'd place him around Kisame though.
Rin maybe Shizune level.
Nawaki i think could've literally ranged form jonin to kage. It all depended on where Kishi wanted him...in his case, dead.
Kawarama and Itama, along with Madara's three dead brothers, could've been low kage level. Or at least high jonin if they had good genes to do so.