I agree with this thread, even though it hurts me to admit it.
the way the raids are structured in this game, are meant to be cleared in several hours.
I can only compare these to what i have experienced before in WoW, where in molten core, we pretty much could only get "so far" to a certain boss, and then had to wait for next reset, so we could get that far again, but this time before slightly better gear, and get another boss.
the difficulty of bosses in this game are not spread out the same.
let's take EV for example (at least from my experience):
Robot at the start > second boss (it is harder, the second boss is easier)
third boss is a puzzle where fear is not important.
4th boss - gear is slightly important, in HM still possible without full columi)
Soa - still don't have to have "the best" gear.
and kragga's palace is pretty much the same:
Bonethrasher can be pretty hard.
then the 2nd bosses are easier.
then the 3rd boss is still easier than bonethrasher,
the 4th boss is the hardest.
Kragga is very simple, and doesn't require the best gear.
tldr: the bosses difficulty is not spread in a higher steps structure. each has it's own difficulties, but are all doable right at the start.