Perhaps adjusting the difficulty level will help. Never encounter in 50h a fight to take more than few minutes. A mark for recommended level for a specific quests will only create confusion. Taking a quest while you are under recommended level doesn't give more xp (it shouldn't), at same level doesn't guarantee the success, doing the quest when you are 10 level above should not affect the reward. If you insist on going at low level in area which is locked by the blight and find there is more than you expected, lower the difficulty or come back later. I know hands holding is a sort of requirement for modern games but at some point that is also irritating. Is not hard to figure out what to expect.
I honestly dont understand what you mean. I did the exact same thing as the OP - simply trying to do a side quest before continueing the main story line. There was no indication at all that this quest would end up vs a lvl 25 boss mob - it was inside an area we had already visited earlier. It doesnt even have to say a specific level it could just indicate with a red dot if the quest was 10+ levels above you or something. Once again - its not a difficulty problem.
