What a thought...we'll have to form opinions of people based upon what they write, not on points that could always be faked or whored. Popularity is an incredibly stupid measure of quality. I'd like to see the up/down arrow on threads replaced by a simple view counter, too.
It's not about forming opinions though - it's about deciding what order to sort posts. Sorting by date / view count / upvote count is pretty crap. We only get away with it now because there aren't many people posting. That's changing.
Pretty much all social networks these days have some kind of "karma" like score, though it often isn't visible to anyone. Obviously in the fediverse it would be visible (though maybe not activley promoted?).
The best karma implementation that I know of is the one on Stack Exchange, though I'd like it more if it wasn't so easy to have a high score just by having been on the network for a long time (my score over there is ridiculously high for someone who barely participates these days).
Just because the current system doesn't do what you want, you think going back to a system of cheating and popularity contests is good? Think carefully about that. Unless you're the sort who also refuses to listen to music that isn't on the Top Ten list and only goes to blockbuster movies. If that's the case, honestly the Fediverse may not be the place for you.
If I wanted to use Reddit/Twitter/etc, I wouldn't have deleted my account on those two platforms. Definitely don't want the fediverse to go that direction.
But I personally believe the problems with those platforms are 100% the fault of the people running the place and the bad decisions they have made in the past and will continue to make in the future.
I think a karma based ranking algorithm, designed by a community that has the right intentions (find good content, and sort it at the top), will work well. Also I think the fediverse is uniquely able to find the right algorithm because each instance can potentially run a different ranking algorithm.
The same way some instances have "vote down" and other instances only have vote up. Time will tell which approach is better, and all the instances will surely adopt the best one.
It may indeed all work out, but I cannot see any possible benefit at all to karma. No matter the intention, it allows opinions to be formed without reading content. People will almost always act like sheep, and too many people will associate karma with legitimacy. I think it would be an incredibly foolish thing to adopt it.