Something really weird is happening in the current WOW expansion compared to previous iterations. In times long past people would often wait 8 months for new content, and sometimes the wait would even go over a year. Hardcore guilds in particular would grind like maniacs for a couple of months to beat the current tier and then go into maintenance mode for half a year or more waiting for something challenging to do.
Of course a lot of guilds weren't hardcore, so they would slowly farm their way through the difficulties slowly grinding their way up the ladder. A guild wouldn't necessarily be a Normal guild, or a Heroic guild, because they could quite reasonably spend that 8 months working their way through one difficulty after the other.
The current expansion, Legion, isn't like this. The expansion has been out for seven months and we are now seeing the fourth tier of raid content added into the game. Blizzard is on a pace to add a new raid every two months, though admittedly one of those raids was quite small. The difference here is that most guilds do not have the time to grind all the way through the game before something new arrives on their doorstep.
If your guild wants to get through all of a big raid in the roughly nine weeks allotted then you have to kill a new boss every week. If, like many guilds, you want to be a Mythic guild but need time to farm up gear in Heroic first then you have to kill Heroic *really* quickly before moving on to Mythic. The top tier guilds do this in a single week of course, but guilds like mine took a few weeks to kill Heroic and are going to be looking at a new raid having only beaten 3 bosses in Mythic mode. My guild *might* kill a fourth boss before the new raid lands but I would bet against it if I had to bet.
This accelerated schedule is really weird. I am used to the idea of cleaning up easy bosses fairly quickly but spending weeks and weeks grinding away at the hardest bosses to accumulate enough gear and practice to get them down. This new way where you get nine weeks to beat everything and then you move on is a serious departure.
I think it is great.
I bet the most hardcore guilds will experience massive burnout because of it. They go so hard that their players *need* six months break between spikes of playing to have their lives work at all, and when they get eight weeks of insanity followed up with one week of downtime it isn't sustainable. Some guilds will simply find the small core of people who are willing to play twelve hours a day for the foreseeable future, but most of them will give up and go way more casual.
But what does this mean for people in the middle like me? I play a lot when new content comes out to see all the stuff and power up, but I usually quit WOW when faced with the looming prospect of farming the same stuff for eight months. How will I react when there is constantly something new to do? I was feeling a little burned out this week, not sure I wanted to keep on raiding, but a new raid, new stuff to do, new power to gain, at a reasonable rate of return on time.... that might change things.
What it means long term is that instead of lots of guilds slowly grinding their way through content there will be a lot more churn. Get it done fast, or don't get it done at all. However, moving past old content quickly and having a steady stream of new stuff will probably make Blizzard a lot more money as it will keep people like me paying into the system.
I also think this will push a ton of guilds out of Mythic difficulty. Many of them are just there because they need something to do when Heroic is cleared out, but if there just isn't much time to get Heroic down there isn't the pressing need to push into the hardest difficulty. Mythic, with its fixed twenty person roster size, is a giant pain to organize, and if you can avoid that mess you probably want to.
My guess is that a quick release schedule like this will lead to greater stratification in guilds, pushing them to just stick to one difficulty setting or another. It will smash a bunch of the top guilds, but be good for the masses of players because there will be so much to do. Blizzard has been saying for a decade or more that they want a faster release schedule, and it seems they are finally in a place where they can deliver it.