1) Definitely not. They've said in the manga before that the Kyuubi's chakra is poisonous. Imagine how much more powerful Naruto might be if he didn't have that poison. Also, he can't control it, and if you can't control it in battle it's useless.
2) He only managed to beat Pain because the battle didn't last more than a few minutes. The final battle against Deva Pain was only won because each Pain had only one ability and his gravity attacks had timing problems. Also, he wasted a huge amount of chakra on that gravity sphere thing that the 8-tailed fox broke out of. He also had plenty of preparation by setting up clones to absorb natural chakra. How will he do in battle if he doesn't absorb natural chakra beforehand and doesn't set up clones?
3) That's exactly what clumsy is. In the middle of a fight (especially against a fast/observant/intelligent opponent), you can't say "give me a few minutes to put together my ultimate jutsu!" In sage mode Naruto was able to make Rasengans quickly and without clones, but again: Sage mode is extremely limited right now. We all know Naruto can perform miracles through training, but where his sage mode is right now is not good. More training will help, obviously.
4) Yes, I forgot summons. So he has 4 jutusus he can use: Rasengan, clones, transforms, and summons. Hardly a well-rounded ninja, and hardly as versatile as other Ninja's we've seen. Compare to Sasuke: a whole series of Fire jutsus, a whole series of Chidori jutsus, amaterasu, tsukyomi, susanoo, summons, chakra-infused weapon skills, great taijutsu, and whatever else Orochimaru taught him. Really, it's not a fight. Isn't Naruto still only a Genin?
5) Tsunade said that her special healing abilities caused her lifespan to shorten when she used them in the fight against Orochimaru. It has also been said that the fox's chakra caused Naruto's skin to burn off, which decreased his lifespan.
6) What could naruto possibly do to beat Sasuke? One shot of Amaterasu would kill Naruto. It is impossible to extinguish and burns until whatever it touches is devoured. Plus, it goes wherever Sasuke looks, and Naruto can't move faster than Sasukes eyes can. So Naruto could create a clone, but Sasuke's sharingan would see the clone. Susanoo would make sasuke immune to Rasengan and frog katas. Plus, Naruto can't use Raisen Shiruken against Sasuke because his fire style attacks would turn it back against Naruto with more power. Sharingan could control the fox chakra if Naruto used that. Maybe Sasuke could enter Naruto's subconscious and unseal the fox entirely, and then Naruto would have to fight the fox. Naruto would be powerless inside any Genjutsu, he has not shown an ability to resist them any time one has been used on him.
At the moment it's not a fair fight. Kishi has given Sasuke too many abilities and has given Naruto far too few. Things are only going to get worse when Sasuke uses Itachi's eyes (and he will, eventually). Mangekyo sharingan are too powerful and Naruto has no known way to defend against them.
1.) He couldn't control it because the seal on his stomach has been tampered with for so long and to many times. People added more seals to it, degraded it, restrengthened it, etc. It's like have a clear tube with flowing water suddenly stuffed with junk that the flow becomes blocked or disturbed. Since his meeting with his dad, the seal was stripped and recreated, the Kyubi's chakra is now flowing nicely, who knows what abilities he can perform now.
2.) Again, Naruto needs time to perform the required nesseccesaties to use sage mode. But hey, how do you explain him in sage mode after his encounter with his dad? You think he wasmeditating while in kyubi form? I doubt it. Again, the Kyubi's chakra interfered with sage mode, but now the seal has been reestablished. Do you not think he possibly has more control over the fox now then before? Don't you think that this control over the fox enabled it to not interfere with his sage tech to go into sage mode rapidly?
3.)True, I agree with you there, he definately needs more training in his sage mode. Even though Ma and Pa frog thought him a pro at sage tech and mastered it more successfully then Jiraiya, he still can't take on Mangekyou without more control over the sage tech.
4.) Naruto and Sasuke are complete opposites. Sasuke has limited chakra, he will tire easily. His jutsus like susano'o and ameterasu will drain it rapidly. Naruto on the other hand possesses immense chakra reserves without the help of the kyubi or sage mode. And even when his chakra is depleted, he can go into sage mode for unlimited nature chakra, or kyubi mode(if mastered) for unlimited dark chakra. Also, I higly doubt Susano'o will stand a chance against a fully formed Kyubi, and controlling someone with the MS is genjutsu. If Naruto does control the Kyubi, then he is basically invincible to the Genjutsu. If naruto falls into genjutsu, the kyubi will release him, if the Kyubi fall to it, then Naruto will release it. Both can't fall into genjutsu at the same time as both cannot be out at the same time.
5.)Completely true, Tsunade did say that every time Naruto gets that cloak and then rapidly heals the injuries with the kyubi's chakra shortens his lifespan.
6.)Naruto is a senjuu warrior, and his dad was a wind user while his mom was a water user. For all we know, Kishi might introduce a kekkei genkai that Naruto never knew he had. Plus, Sage mode increases his phsical strength, maybe it could help in slowing down the ameterasu from hitting him while he has time to escape. Also, like Susano'o, when Naruto has the Kyubi's cloak over him, it's impossible to get near him. Touching him poisons you, Naruto's chakra will burn, thrash, etc. to all those near him.
At the moment, I believe it is a very fair fight, but I believe your right about Sasuke resorting to Itachi's eyes, in which case, Naruto definately needs more training, no questions asked. What we need to look at now is who will teach him? he's surpassed everyone in the village, even his dead father in power, but not brians. Maybe he can go take physics, calculus, and other classes to improve his thinking capabilities! o.o