I would like to see the game remove you from the Team Up you are waiting on, when you join a through the sigil instead of a four man team, or timing in after two minutes. It really stinks when you forget to log off the team up and get some ways into a dungeon then suddenly find yourself in another one just starting.
Also I would like to see a feature where you can click on the name of others joining a Team Up while waiting, and see their stats before the time runs out and you find yourself in a dungeon with people who don't have the experience, or power needed to win.
Regarding your second option, it would be nice to see at least the level of your future teammates, but I'm guessing it's not there because that shouldn't stop one from teaming up with another to get a common goal done?