Dear moderator, you locked my last thread re: this as you thought we already received an answer to the question. However, the answer given was related to the Recent Games tab in Steam and not in game Steam Friends List Support.
My suggestion now, would be to add in game Steam Friends List support. It would be great to be able to for example: right click a players name in a lobby and have an option to send a Steam friend request. Or perhaps a good place for this would be under the player options menu in lobbies.
Currently it’s a bit of a pain to find someone you’ve recently played with as you have to search their name in steam, and if there are many players with the same name it can be a hassle.
This may help new players team up easier and help keep players around longer.