It's clearly that bots just abuse it and most people on boards form their opinion mainly on how many votes a thread/comment had than what's someone is really saying.
Those 2 together really doesn't make a good pair, allowing those bots user to have basically a monopoly over boards and influence people opinions as they wish (I mean obviously not everyone but a lot of people will take anything with big green numbers as an absolute law)
Instead a rework for system would be to categorize what's a hot/top thread by the number of people that engage in them, like commenting and replying.
That can only have only positive traits so far, for instance:
1. Bots will become completely useless, as they can't kill threads they hate and highlight their owns
2. When someone posts something you actually will get a feedback why people agree/disagree with op view points, instead of just vote and scroll to the next, so everyone will understands the reasons instead of the classic "+1" "-1"
Another options would be to keep vote system but also force the voting one to leave at least a comment in that thread before vote/downvote any content there.
Ofc what I think of is no way a perfect system but I believe that will solve some of big issues this boards have, especially in last week.