In ICC I was able to kill lots of things. We had 25 man pugs clearing the first two wings with no problem. That's because the difficulty curve was pretty good and it made for a rewarding encounter, i.e PROGRESSION. Saurfang, the last boss of the first wing was the hardest, with the bosses leading up to him ramping up difficulty (aside from loot ship) and then the next wing same thing. Festie and rotface harder than Saurfang and PP the hardest of the wing. Same for the next wing. Right till the last wing with LK being the hardest. That's how you design a raid to last. Not rip the knob off the difficulty on the second boss and call it a day. You need a mix. If you want to do it linear or you want to do with choice I don't really care. But you need to give players something else to go and do in the raid after beating their head against shitty gear check bosses for hours and hours on end. Icc didn't have that mind you but Icc had a better curve so you hve some success behind you and motivation to continue. After Jinrok you basically hit a wall.
Hey just keep pushing players to lfr. It gets harder and harder to recruit for normals and make a normal raid every day.