I can imagine higher-level characters may have it easier - possibly - just because they have more tools at their disposal. But I have no heirlooms (I have maybe 1500 gold total across 5 accounts) and am only level 43. And these instances are freaking brutal - and I can't just gain a level or two and then come back. If I do, they'll have scaled up and will be even harder than they were before. I don't see how new players can do these without being carried by someone else.

Any boss with a timer mechanic is almost unbeatable for me now - because I can't pump out enough damage with only 3 DPS.