In a way I agree with this one. Everything should have a minimum and a maximum ilvl on it. Already mentioned it in another place, but the Royal Menagerie is a good example. Not having a cap there means you've now got healers and DPS with more HP than a tank in near-minimum gear. It makes the fight so trivial that you can practically ignore most of the mechanics. Even Akh Morn is solo-able as a healer. I've accidentally brain-farted and walked dead-center on top of a proximity AoE and survived it. Get anywhere close to that in ~290-310 and you're a goner.

This type of thing happens in some of the 70 dungeons too. I end up going in on WHM with more HP than the tank sometimes. I end up tanking quite often in those cases too, unless I really take it easy on the Holy spam. Usually I'll just keep on going and tank them since mobs in cap dungeons hit for basically nothing as soon as you outgear them.