I wouldn't say that. Remember, that was Genin Lee. He's Chuunin now.
If you accept the movies as semi-fact, Lee can use 5 gates with no real harm, and can even mix in his drunken boxing.
I'd say Lee has at least as much potential as Gai. If not more. He just has a more linear progression to his ability.
I think it's more that we just haven't seen Lee enough lately to judge properly. I think he'd hold up as one of the more dangerous members of the Konoha 11.