hasselh, group chats are designed to have history logged into .txt format. Changing it would require changing all chat related plugins.
It was this way because for chats was used mostly IRC/Jabber where are many users (20, 50, 100...) and many events and all that would bloat your profile very easily and quickly - even that .txt file could grow few MB per day depending on how much how active chats you have. And having that much data in a single file together with contacts and settings doesn't sounds good.
However, with WhatsApp, Facebook, VK and similar networks, where are multi user chats with much smaller amount of people, and all messages are really related to you (not like in public irc/jabber chats) it makes sense to save them into profile.
I'd like to see improvements in Miranda regarding this multi user conversations to behave more like private conversations and not like public irc/jabber chats. It will require much work across core and chat plugins. So probably ghazan have to say something about this.
