I made a few feature suggestions on this pagination topic that I now want to move out to become a separate topic.
Today, in large topics, you can click to see a “summary” of a topic (topics that had a lot of likes or replies), but users have to click a button to turn on summarization.
When a topic gets way too large, Discourse should summarize the first N posts by default. Make users click a button to unsummarize the first N posts.
I think this could be especially useful in very large PM topics, which are often just private chat conversations anyway. Forcing users to start a “new” PM topic just to continue chatting is just creating hassle.