I wonder about your (2) idea... If the goal is to reduce the effect of bots that vote exactly the same, then ok, sure. (Though if it became common, I'm sure vote bots wouldn't have a hard time being altered to add a little randomness to their voting.) But I'm not sure how much it would help beyond that, since if it's not just identifying _exact_ same voting, then you're going to need to fine tune some percentage-the-same or something like that. And I'm not sure the same fine-tuned percentage is going to work well everywhere, or even across different threads or subforums on the same site. I also feel like (ignoring the site-to-site or subforum-to-subforum differences) that it would be tricky to fine tune correctly to a point where upvotes still matter. (Admittedly I have nothing solid to base this on other than just a gut feeling about it.)

It's an interesting idea, and I wonder what results people get when trying it.