Hmm. I'd say Aizen ordinarily, but KS and Immortality are probably his strongest attributes out of many strong ones. With those being restricted I think Naruto would take it so long as he didn't resort to melee. Even with reiatsu crush off, Aizen desolves whatever gets near him. Biju dama spam and Naruto could put him down. Fragor spam would be troublesome as well but IC Naruto does it first. I'll go with Naruto here.