I agree with xanbcoo and DarthEnder. Naruto might seem simple, but that's because he is. He is the most single-minded loyal ninja in the bunch from what I've seen. He's single-minded in his focus to become Hokage and in finding Sasuke, and that drive is a large part of what makes him so strong. The nine tails is only a part of his strength. It's his heart for his friends that makes him truely strong. That is the real strength that he used to influence Gaara and turned him to be a powerful ally. It's Konoha's "will of fire" 10-fold.
And he's learned a lot since being known as the dropout. He may only know two good techniques, but he has also mastered them far faster than anyone could have expected and found creative ways of using them. Remember his adaptation of Sasuke's tiger move during the Chuunin exam using kage bun nujitsu? And how he managed to use it to complete the rasengan? He was so persistant while learning rasengan that he was skipping meals, which we know is a really big deal for Naruto as much as he loves to eat. Rasengan was Hokage #2's signature move that took him 4 years to perfect, and Naruto learned it in a couple of weeks. And wasn't it that determination that convinced Tsunade to accept the job as the 5th Hokage after she made a bet with him that he couldn't do it (and our favorite "perverted hermit" knew that it was a bet Naruto couldn't win)? Like DarthEnder said he's the #1 ninja in surprising people, and he's only going to get much, much better as long as he keeps his focus on becoming Hokage.
By the way, just using the nine tails for any old reason is not a good idea. It takes a lot of him to use it, and he still needs to grow a lot to learn how to use that power under control. We saw what happened in the battle with Sasuke.
So don't diss the poor guy so much. He is the title character after all. [img]i/expressions/face-icon-small-happy.gif[/img] He's going to unify Konoha in a way that no other Hokage has ever done.