I don't believe you'll ever get away with not having biased announcers. I think #1 it keeps them in good graces with the top teams so they can get interviews etc. #2 It's easier to talk about how good a team is than blast a team for being terrible.
I think ESPN probably has some of the worst homers in the business. Obviously Lou Holtz is all ND and SCe ( he doesn't even hide it). I like Herbstreat but he can be pretty bad at times, during the Reggie Bush USC years I swear he was handing out reach arounds in the USC locker room, it was pathetic. Obviously there are others and it will never go away, once the Vols are back to dominating again you'll have to beat the bandwagon jumpers to keep them off the train.