Contact List Sorting (message received, online status)
Having now ~30 contacts reveals some small inconveniences that only happen with a larger contact list.
For example, the list is currently sorted by the time messages have been created. So when you finally manage to get an old message synced, the unread message bubble and the contact might already be way down, so you overlook the new messages. Sorting the list by the time a message was received might help with that.
Also, when you have many contacts, some might be inactive and never come online. Usually, only a small subset of users is online and users have a higher interest in knowing which users are online and can be communicated with right away. Taking a users online status into account for sorting or offering the option to hide offline users might improve things here.