I've entertained the idea before too, except more like Groose just became so jealous and hateful that it led him down that path. XDLol I just thought the hatred towards Link through out all the games was going to be something that SS Link and Zelda did to Groose which eventually would turn him to Ganondorf/Ganon and thus hate all future Links for eternity... Sounds good though right?
I thought Groose might have been a reincarnation of Demise(unaware of his own origins), who later becomes Ganondorf, the whole time, until he started helping Link. I never really thought that Groose was evil though.I thought that Groose might be tempted by Demise to join him so that he could get back at Link for taking Zelda away from him.