as a newcomer, the missions are prohibitively hard and it is silly that they have tiered the missions by class.
I found the game pretty much forces you to play with other people, which isn't a bad thing, but you should be able to make progress on your own when none of your friends are online.
No matter how good you get, the missions will always remain hard because of tiering. I can understand how earning credits and XP should be a challenge, but sometimes I just want to relax after a hard day's work and have a battle with the odds heavily in my favour.
I think we should be able to set up our own missions how we want, and then the XP and cash is given on a difficulty basis. The better enemies you face, the more cash you get. But at least give us some choice and customisation as this is probably the most used feature in the game.