"This type of behavior is when a whale creates a bot that simply up votes everything from reputable users regardless of quality. This kind of behavior can be countered by other whales only by pushing the author rewards toward 0."

Unfortunately we already know that some whales are doing this and their is no counterbalance with other whales downvoting such posts - it only happens very occasionally. Most of these posts are of decent quality but even if they were not I'm not sure most whales would flag them. It does seem to be improving though because we have seen less auto upvotes for plagiarising material but as long as whales use upvoting bots the risk of low quality material rising to the top remains.

"Voters that vote poorly will kill the platform. Voters who vote well will help the platform grow."

I agree with this which is why I think using voting bots in general should be a no-no. If the whales don't have time they could delegate their voting (if it is added to Steemit) and until then there will be greater voting power for everyone else when they don't vote. Nobody should get an automatic whale up-vote.

I think the negative voting aspect could work but as you say people will not like that. It would also be interesting to know how many minnows would be required to negate a single whale up-vote. I suspect it would be so many as to make it pointless.