Let me explain this suggestion of mine: "So I would rather make sure that the bottom half of criticism gets an increasing potential for negative karma impact, by applying a weight on the upvote points starting from 1 for the median criticism, and progressing towards 0 for the worst criticism. (goodness can be measured as unweighted votes divided by number of votes.)"

I explain on an example. There are 800 criticisms arrived in Januar 2024, in total. all have their upvote/downvote based points (let us say as of 15 Feb), let me call these "raw points".  We put them in the order of increasing raw points. The worst let be -5, the 100th 5, the the 400th (the middle one) 25, the top one 110. Now a multiplier "m" is calculated for the bottom 400 criticisms, it will be 1-(400-x)/400 , where x is the rank of the criticism, so x=1 for the worst one, x=100 for the 100th one. 

Now, for example, the worst criticism had raw point -5, and this was calculated as a sum of upvote - downvote points (raw = up - down), let us assume total upvote points 10, total downvote 15, so -5 = 10-15. We now apply the multiplier : final points = m*up - down. In this example, final points = (1-399/400)*10 - 15 = -15.  So the final point will be approximately -15 because a heavy multiplier has decreased the value of the upvotes.

Hi. As I understand the point system has two main outcomes: changes in Plan points, and changes in user karma. (Criticism points are a means to both.) 

Let me adress the proposed changes in user karma based on criticism up/downvote. The original suggestion is that "downvote points will lower the criticizers karma by N point, an xN number of upvote points will raise the criticizer's karma". In this case most criticism will end up increasing the user's karma, some more, some less, but the balance will be almost always towards upvote, becaus people are friendly, they are more ready to upvote than to downvote. The final result is that even if you are doing rather bad criticism (like around bottom 25%) you always get a little positive karma and if you are busy enough you end up as a superstar while in fact you are bad. So I would rather make sure that the bottom half of criticism gets an increasing potential for negative karma impact, by applying a weight on the upvote points starting from 1 for the median criticism, and progressing towards 0 for the worst criticism. (goodness can be measured as unweighted votes divided by number of votes.)

It needs to be defined when the user karma impact becomes effective. For example after 2 weeks the criticism was placed. Then it may be necessary to evaluate and amend the karma impact once more, maybe after 8 weeks.

The main issue with the system will be low level of user interaction in terms of criticising and voting. I have gone through this when I designed and operated a similar system. Some measures must be identified to overcome this. Here are three proposals:

I would add karma points just for the action of criticising and voting. 

For users in high karma range I would engourage to do much criticising and especially voting. For this reason I would apply a constant monthly karma reduction on them which can only be undone by sufficient karma collected through criticising and voting.

For the most active people (top 20% in terms of number of votes in the given month) for those in the higher karma range (top 50%) some additional appreciation is needed, like placing a list of heroes, or similar.