I want to agree with you on some points because I was getting one shot deaths from a lvl 24's Fatebringer and I'm a lvl 29. I'm pretty sure you can't one shot anything 5 levels above you in game. Boss mode, not on. But they did say a lower level with a maxed out weapon should still be a threat. That's a bit contradictory to the 3 level "league" range. I don't understand it either, but it's not stopping me from going after that gear for level 30.