I'm not sure about Five being that agreeable. I've been watching a lot of Davison of late and he's downright grumpy at times, and quite short tempered.
I remember reading an interview when I was a kid that Davison drew upon the First Doctor a lot and wanted to convey at times a sense of a cranky old man's soul in a young man's body (or something to that effect). But I also think he drew upon the occasional self-depreciating nature of the Second Doctor as well.
I think the idea of the Fifth Doctor was to sort of be the opposite of the frequently larger-than-life Fourth Doctor. To be less whimsical and a bit more serious.
I think every Doctor has had a degree of crotchetyness and arrogance, I think the problem with Colin was that both these attributes were dialled up to eleven with him.
I remember all sorts of early criticisms aimed at the Sixth Doctor, generally falling along the lines that he was too much of a departure from previous incarnations--too sarcastic, too flamboyant, and even too violent.