A Couple of Suggestions. :)

1. I was running +2 for a bit, then I went and got a snake mission and went inside before remembering, HEY that would probably be a little hard at my level.

So I exited.. and couldn't abandon because it was already started. I could change diff, but it's locked at that point because I entered. I didn't have any other missions, so I had to go halfway across Mercy to pick one up so I could select it and reselect the snake mission.

I don't know if there's another way to do this or not, but I don't see why you can't abandon a mission once you've entered when there's a workaround like that.

2. I think the Supergroup guy in Port Oakes should be a contact you can see on the map. I've checked all the different types and he doesn't show up.

1. /leaveteam
If you're solo, it will make you quit the team you're on, abandoning the current mission.

2. Supergroup Registrars don't show up on the map. I wouldn't object to them being added. As a long-time player, I know where to go to find them, but for newbies, I'm not sure any hint is ever given.

Add Registrars to the map (seriously, has it been this long??), and maybe make them a little more commonplace. Currently they're in Atlas Park and Port Oakes, maybe add another one each to Talos Island and St. Martial.