The only way I can speak to the tool is my experience as a very long time redditor. Karma points tend to serve a few functions apart from ranking comments, which I assume this forum won't do because of its structure. It's important to remember that most people don't click the button there unless there is something exceptional about the posts.
The place I see it most used is to signal strong disapproval for content that is deemed wildly inappropriate. You'll often see content with negative scores in hundreds, and reddit responds to this by auto-collapsing these posts.
The next place you see it use there is to signal "I agree" or "I disagree." That use is explicitly not the intended function of karma on reddit, but it's how it's used by most people. This leads to group-think which is often bad for the forum. The way the side deals with this is that their algo adjusts based on karma and time, where a highly polarizing post can still remain prominent.
I also see the karma system use as a show if support for people making difficult comments, either personally vulnerable, or in honest, but difficult or controversial opinions.
Personally, I do think the site could benefit from some feedback on decorum issues, but I also worry about the group-think aspects. If we do use it, I think it would be a good idea to have an explicit etiquette guide on when and why people should be using buttons.