No, I really don't think that Brock's good enough for Misty. Besides, I think she's already chosen a cool trainer she's been following around for "years".
OK, my interpretation with Misty pulling Brock's ear is simple, I think:
The reason why she does what she does is because I think that Misty is really jealous of Brock at the fact that he can freely express his emotion of love whereas Misty can't bear the fact of actually admitting the same to Ash. Of all the episodes I've seen, Misty always throws tiny hints at Ash, but Ash seems to never see them. Brock, on the other hand, always goes in headfirst, hoping that love will come to him. Therefore, some girls reject him immediately. If not, Misty takes care of that. To put it simply, I think that Misty wants to find love first before Brock does. It's what gym leaders do; competing with each other all the time for the renounment.