It's been suggested before, but the actual problem here is that the functions of the up/down arrows are overloaded and used differently on other sites. Some people use them for correctness, some people use them for entertainment. Personally, I think admitting defeat on the UI is the best option here. The arrows should become essentially placebos. Separate the mechanisms for rewarding insightful comments. Perhaps something more like the "thanks" mechanism in some forums where there is a scarcity to the votes--each user is allowed only 5 thanks/day whether they use them or not. The limit could be seniority based. But if I was running the site, I would leave the arrows and just give up on re-educating the masses to use the arrows differently and move on. It's a battle that cannot be won.