Give us the ability to pin and clear private conversations, the ability to look for people we have chatted with before, and the ability to sort them by "Most Activity" or "Recent Activity".

Here's why I believe these should be added.

The ability to pin and clear private conversations would allow us to prioritise important people and clear out the meaningless ones.

The ability for us to look for people we have chatted with before would allow us to continue old topics with people we have talked with before, or even start new ones.

The ability to sort chat by Most Activity or Recent Activity (default) will also help in prioritising chats better.