This question already has an answer here:
I was just thinking, why nodes pick the first block they see when there is an honest split, instead of picking, for example, the one with the "best hash" (number further away from the difficulty cut)?
Deterministic criteria like that would allow the entire network to quickly know which block wins, and everybody would then build on top of that block. Much less hashpower would be wasted on the dead branch.
Unless there's some risk/problem in it I'm not seeing...