Low ilvl requirement for dungeons does not mean it is going to be easy, Pharos at ilvl49 or the extreme primals at the lowest ilvl through out the whole party would be difficult.

High ilvl gear on a character does not mean they are good, not knowing mechanics can easily cause a wipe... and some are unable to learn... like the QQ thread that a mnk made awhile ago about getting kicked from T2 because they kept getting cleaved to death by minis/ads. It was their first time doing it the way it is meant to be done, tank swapping.