top players are the ones who (or at least most likely to) play tennis at a high level day in and day out, do you want a mug player to make the upset only to mug out on the next round? it's certainly most exciting watching the top 8 making it to the QF and colliding in the latter stages, nothing better to watch.
Would prefer to see the bottom end come up, and push the top end to be better. But I sure don't want to see some clown get hot one day, then screw up the semis. Seen that to many times. Just need more solid depth that can produce multiple quality matches in a row.