He couldn't have been more off on the character of Spider-man. In fact, Spider-man wasn't even a character, he was Peter in a suit, and that is not Spider-man.
Peter especially in his early years, became a different person in the Spider-man suit. Just like Bruce Wayne becomes a different person in the Batman suit. As Spider-man, Peter finally gets an outlet to express the confidence he doesn't have as Peter Parker. This is why Spider-man is a jabber mouth when he's fighting his enemies. That and because Peter has said that he thinks he'd go crazy from the fear of battle if he didn't run his mouth to distract himself.
The cocky attitude and quips are essential to Spider-man's character. Having Spider-man remain a near mute as he did in Raimi's movies is just as wrong for the character of Spider-man as it would be to have Batman cracking witty one liners.
By basically eliminating this aspect of the character, Raimi failed to show us Peter's confident side, and it also removes a reason for people to believe that Peter is not Spider-man, because Spider-man is much more vocal and boisterous then Peter.
And in regards to the character of Peter Parker, Raimi barley showed us any of Peter's intelligence, and completley disregarded his engineering skills. Peter does not merely spout a few intelligent sounding sentences like he does in the movies, he actually creates and invents things. Raimi showed us none of that.
Also, by the time Peter was in colledge he much more confident as Peter Parker. Raimi didn't show us that either, he had Peter act the way he did in highschool, which wasn't accurate to the character.
Raimi did an average job on Peter's character, but he left much to be desired.