Here's a tiebreak idea: in the event of a drawn match the title becomes vacant. The world champion is supposed to be the best player in the world, and if he can't beat the challenger then he is not that.
This would put a gun to the head of both players: win or get nothing. That would make the games sharper and there would be more decisive games.
Of course, it's not perfect.
Ed Yetman, III
"I will not be pushed, passed, isolated, blockaded, doubled, undoubled, or promoted!"--The Pawn.