In the Nighthold raid in the latest WOW patch there are 3 clear tiers of bosses. The first 3 must be done in order and are easy, the next 4 can be done in any order you like and are moderate in difficulty, and the last 3 are extremely hard. This has lead to a situation where a huge number of guilds, several thousand at least, have defeated the first 3 bosses but are stuck unable to defeat anything else.
Recently I joined a new guild in order to be able to raid Mythic difficulty and I think we are the classic example of one of these guilds. We have some really good players who could find a spot in a top guild if they were willing to play 40 hours a week but since they aren't they hang out with a 6 hour a week guild like the one I am in. We have some solid players who are good enough to do the medium difficulty bosses, and we have a few people who aren't good enough to be in Mythic difficulty at all but are getting carried along. This has translated to us beating the first 3 bosses without serious difficulty but being totally unable to get any further.
Many people are complaining that the step up from boss 3 to boss 4 is too much. I think that is a fair complaint, but it isn't necessarily that boss 4 is too hard but rather that boss 3 is too easy. When people wander into an instance and find a nice difficulty curve from boss to boss you don't end up with all the guilds stuck at one spot and every new boss you fight feels like a real success when you finally down it. When a middling boss is trivial but the next is a serious challenge then people get frustrated because they are used to easy wins and suddenly they can't get anything done.
The hardest boss of them all is the roster boss. You can't maintain a roster of 25 good players because you can only bring 20 players so you have to bench 5 of them every night. If you try to do that those 5 benchwarmers leave to find guilds where they actually get to play. You can maintain a roster of 20 good players and a couple hangers on, but then when a couple of your good players quit you suddenly have to bring the scrubs along just to fill up the raid and they make you lose. It is really difficult to recruit people because nobody wants to be the 23th raider because they get benched and nobody wants to be the 18th raider because then their guild is carrying scrubs to fill the last two slots.
You also have the problem that since there are thousands of guilds at the same point in progression you are fighting with everybody else for a limited pool of recruits. It is hard to differentiate yourself from the pack, and you pretty much have to hope that your raiding schedule uniquely suits the potential recruits that are looking for a home.
My guild is having all these issues. We get some new recruits but mostly they are terrible players. We can't just bench them freely though because we don't actually have enough good people to fill those spots. What do you do when a new recruit fails totally at doing important parts of the fight? Kick them, and run with 19 people? That isn't a good plan. Just run with them and let them suck? That makes your good raiders mad because they are carrying people who are bad or lazy.
It is a complicated mess, and right now my guild is dealing with all of this. We are just one of the thousands of guilds stuck trying to get a 4th kill, and our roster is enough to fill a 20 person raid, but just barely, and we often end up bringing along terrible recruits or puggers.
The raid itself is a lot of fun though, I can't deny that. It is just the logistics that are a nightmare. This is pretty much the way it has always been, and I am just glad I am not the one whose job it is to do the logistics.