Sasuke won't learn senjutsu because Naruto has learn to control it. Naruto is the body which means body related techs, like SM,KCM,BM and Sasuke is the eyes because he is using eye techs so far. Sasuke doesn't have the amount of chakra required to become a sage because he doesnt have the body for it...
I beg to differ.
Curse seal mode is a version of sage mode. Sasuke has been absorbing natural energy, before naruto did so.
Juugo mentioned, how sasuke his body, is compatible with juugo his flesh and chakra.
I think it would fit, if the battle between naruto was eye sage, vs body sage.
Sage vs Sage. Sasuke would be a totally different sage anyway. Different fighting style.
Especially if its similar to curse seal mode.
Naruto still has Kurama mode, his rasengan versions and Bijoubomb.
Frog kumite. Probably FTG in the near future as well.
Sick regeneration. Bigger chakra reserves, even without kurama and naruto has special chakra which is capable of withstanding the poisonous chakra of kurama (dunno if it still has that effect now that they are friends, but naruto's chakra remains special).