Jumping between iMessage, telegram, WhatsApp, and slack, the big missing feature in iMessage for me is the inability to delete messages. It’s way too easy to select the wrong photo or text the wrong person and have to awkwardly wiggle your way out of it. WhatsApp shows the message was deleted and has (had?) a timeout for the delete which feels like a nice implementation. Telegram’s deletion functionality of your and the recipients messages without leaving a trace might be overkill for iMessage.