He won't know he's outmatched until rock lee already has a hold of him, and by then he's not letting go, A few barrages of punches and aang will be severely injured, Aang is mobile but I'd argue lee is way more mobile, Lee can also dodge while simultaneously closing the gap between him and aang by pursuing him. Aang does not use fire bending that much in character and rock lee is capable of dodging water AoE, And even then he doesn't make tsunamis from water bending, he shoots out geysers and stuff like that, He doesn't use large scale AoE in waterbending if memory servers me right, and no? Aang is no dodging all of lee's attacks with seismic sense, Rock lee is way more skilled and agile than aang, He also has some moves which is mid-air like the flying lotus or just him punching gaara mid air in their fight, seismic sense is most definitely not predicting all of lee's attacks, And his seismic sense isn't even very potent, its way less potent that toph's