Is not the most powerful character in Bleach. Yama-jii could whipe the floor with him. Kyoraku could Shikai him to death. Urahara Kisuke can slaughter him and Hitsugaya could trap him in an ice obelisk before Ichigo even had a clue what was happening. In fact, there is a whole host of people who are a lot more powerful then Ichigo. Can we please just accept this fact and move on?
I am sick and tired of people making Ichigo out to be something he is not. He is not Goku. Who, as the Legendary Super Saiyain, was literally the strongest person in the universe. Ichigo is special and not just because he is the main character but his "specialness" is due to something else entirely. As we have learnt from the most recent chapters, what makes Ichigo special is the fact that he has captain class reiatsu and is most likely not under Aizen's perfect hypnosis.
Let me put it this way. In Lord of the Rings, the most special character in the entire book was Frodo. What made Frodo special was the fact that he was so ordinary. He had no ambitions beyond wanting a cup of tea and a good book. His ordinariness made him immune to the influences of the One Ring, which corrupted quicker the more ambitious a person was. The ambitions didn't even have to be anything bad. Even the most noble of ambitions could be corrupted by the One Ring.
Likewise, what made Harry Potter special, wasn't his skills in magic (loads of people were better then him) but the fact that he had a piece of Voldomort's soul embedded inside him. Sure Harry Potter was above average in magic and in addition had certain personality traits that made him stand out from the crowd and made him about the only person who could stand-up to Voldomort. But it wasn't just about his power, in fact, it wasn't about his power at all.
This is where Ichigo comes into it. Ichigo is powerful, even at half-strength he has captain level reiatsu. However, in the grand scheme of Bleach that means very little. He has limited control over his power. His reiatsu is rough and he is years away from fully mastering his power. To say that he is more powerful then someone like Yama-jii or Kyoraku or Urahara is just idiotic. Not to mention that it misses what truly is remarkable about Ichigo. More then his strength it is his personality and ability to make friends without trying that is proving a great asset to Ichigo. Ichigo's specialness isn't about his reiatsu, that's impressive, but it goes beyond that. The sooner people accept this, especially Ichigo fans who aren't doing themselves any favors by putting forward idiotic claims of Ichigo's greatness, the happier we all will be. Not to mention, we can finally start appreciating Ichigo for what he is and truly see what makes him special in the Bleach verse.
Put another way, Ichigo is the hero not because Ichigo is the only person powerful enough to defeat Aizen but because by being a conduit Ichigo has brought together the Gotei 13 and the Vizards. Bringing forward an united front of all available Shinigami to counter the Aizen threat. He has also managed to get the last remaining Quincies into the mix, not to mention the only two non-quincy humans in the entire world who could be of use in the war against Aizen. Of course, the crucial thing that makes Ichigo the Frodo/Harry Potter of Bleach is the fact that he hasn't seen Aizen's shikai. THAT is the thing that makes Ichigo the only person able to defeat Aizen when other, stronger people cannot. THAT not his power, is why he is the hero. The Hero of a story doesn't have to be the most powerful person in the story. The Hero of the story just has to be able to do something that no one else can. This is by no means a bad thing. It just means that Bleach isn't Dragonball.