I could see a version of Twitter that is similar in a way to the latest Instagram release (allowing for up to 10 images per post). So on Twitter you could have up to 10 tweets in a single post. Each still 140 char. Only the first one shows up in everyone's feed (just like it does today) and you swipe/scroll/page to the side to see additional pages. If the first 140 is intriguing enough people will scroll sideways to read more.