One part of the game is to try out different strategies and combos.
Instead of waiting on the next update to hope the mission you need is made easier. Try to improve your character through gear/skill and then try the mission again.

The mission/quest examples given aren't hard at all. I really have no idea how you've known dozens of people stuck on mission 2-3, it can be duo'd at lv25. Also I can't think of a single quest/mission that requires a specific setup. (unless your stating a basic setup of healer/dd/tank is specific)