he's far from invincible atm, and there's no such thing as invincible, but he could well come close. the closest is tobi atm.
naruto has a lot of potential upgrades which are quite easily attainable, especially considering he can train with clones and progress amazingly fast. i'm listing these with order of likeliness and ease of attainment
1. co-operation with kyuubi ie. immunity from genjutsu, ability to enter tailed beast form which probably surpasses km, ability to transform into the 9-tails itself, and tailed beast bomb. also the kyuubi wouldnt steal his chakra anymore, which is critical.
2. learn the tailed beast rasengan, he's quite close and it will definitely be his most powerful attack. i'll be very surprised if susanoo survives one of these tbh
3. mix kyuubi mode and sm, he's already shown a hint of this vs nagato. he would have massively boosted strength and speed, sensing of malice plus threat perception, chakra arms plus frog taka... in short, devastating.
4. learning some of his parents techniques, ftg of kushina's sealing jutsus, naruto is an uzumaki after all, he should have some sealing techs. it would make him much more versatile.
5. learn rasengan with one hand, it will free up his clones to do the same and distract, and would reduce the time to set up his attack dramatically (like minato vs kyuubi)
6. learn a second element, using his clones he could do combination techniques and increase their power exponentially with minimum chakra cost. added to this, learning some proper wind jutsu like danzou, that wind hovering technique for example would work really well with frog kumite.
and as for the fanboys SHUT THE **** UP these ppl can say whatever they plz naruto,sasuke,itachi IT DOESNT MATTER stfu
