Gawyn got assassinated as a character since he was written into a corner.
Agreed. He had so much potential! It is almost like RJ thought: 'Huh, looks like I have too many characters. I don't have time for this one.' See also: Demandred.
My *main* gripe with him is that he tends to pass the buck with EVERY LITTLE THING.
Mat seems the most comfortable with being Taveren/bring led around by the nose by the Wheel/Pattern - 'oh, I did this because ...uh... I felt like I should and so I did?' Perrin and Rand keep feeling the tug of the Pattern, but tend to fight it. It does get annoying that Mat seems to keep getting away with passing the buck, though.