I must admit, Sonic is very out of character in these comics. First, the Sonic is an idiot thing is a stereotype and if you play the games, you can tell it's not true. Also, while Sonic may be embarrased by Amy's flirting, he doesn't act like a jerk to anybody, strangley, Amy especially. Could it be?
Yes, you are right, the whole "Sonic is an idiot" idea is a bit cliche by now. But one must also keep in mind that my comic-writing skills have improved with time and now I've tried making the character's personalities more original. Tails, for instance, can be a bit of a jerk. And Amy is in the "I still love Sonic but he gets on my nerves sometimes" stage of the relationship.
I'm thinking that most comic authors don't continue a single series for this long, and so the improvement in their skill isn't as obvious, for it is broken up into different comics. But this one is just one comic and so some of the later ones may be inconsistent with the earlier ones.