So as I was sitting in a team up queue waiting forever, I thought of a great idea. Having the option to Team Up with anyone around the spiral from one place. This would enable the feature to help anyone in a queue no matter where they are. Certain places have little to no one joining the Team Up queue (Grimaldi's Cave being the one I've been waiting forever at) so adding this feature would allow everyone to get the help they need at certain bosses and dungeons! I look forward to seeing any replies!
Your idea has merit. While I like the Team Up Portal outside the Bazaar, I would love it to go further, and allow you to enter any mission from there, or initiate team up portal so other can join. This way, you can team up, or access any dungeon you've already entered.
Okay, so obviously the Team Up hub just isn't that great. The improvements that could come up, like Tyler suggested, could include having activating the Team up option on any boss tower or dungeon you have already accessed from that hub. It would improve even more if we were to add the option to have a Team Up friends request option. All Online friends would receive a notification that one of their friends has activated a Team up and then they could join as well to help out. This could be disabled in the Player's settings of course. Just a few more ideas to improve it.