1. Make a bigger deal of lists. Add the lists tab to the top of the page, show the list of lists a person is in next to their name.
For new users its a great way to find people with similar interests. For existing users they let you unfollow people but still check in on them every now and then so your timeline isn't so insane.
2. Add the option of removing inline images/quoted tweets from the timeline it looks ugly
3. redesign, I find twitter so difficult to read its so cluttered.
4. when I say I dont want to see the 'while you were away feature' I do not want to see the 'while you were away feature'
5. Allow me to write private notes about a user or look up all our previous interactions on one page.
6. Allow me to star users - these users tweets are highlighted in some way on my time line
7. when I clikc the tweet permalink why is it a popup then when I go directly to a page its not styled like a popup - this is confusing to some users who think they've loaded a seperate tweet
8. I'd like a daily email of a select group/list/my timeline if 9. Bookmark where I was last. I dont like to miss any tweets.
10. allow me to send group DM's
11. dissappearing tweets. I know this is cipying snapchat/instagramstories/whatsapp but tweeting a phtoo/text which dissappears after a custom amount of time (1 month/year/day/hour/minute) would be brilliant.
12. bring back the third party apps. they made twitter.
13. make trending hashtags easier to see/browse. News articles are always saying x is trending but I never see this.
14. allow me to search tweets nearby. Useful for conferences.
15. Dont include URLS in character count, I think this was supposed to have been added but I've not noticed it working.