Twitter's earlier message length limit had one thing going for it: it kind of forced everyone to choose exactly the right words to get their message across. Much of the fediverse activity stream looks like unintelligible garbage. It lacks clarity or sufficient context to be understood. No one is going to click on a link without knowing what to expect; no one is going to waste time trying to figure out unclear messages. We skim, shrug and move on, but I think many people simply give up and go somewhere else.