I just know based on my AQ experience, that as players, what took us months 14 years back took two nights to surpass the very first week to wow classic gold get a largely casual father and mother guild of raid loggers. We full clear in a single raid night and I think this is week 4?
I guess Naxx May take around 3 weeks into a month for us to complete clear, and that's an incredibly conservative estimate. I'm thinking 2 weeks most or to at least get to KT in 2 raid nights.
Twin emps/Ouro/Cthun are all about the difficulty average of naxx. Early naxx bosses will fall over fast and some guilds will likely get blocked on later bosses to get a bit like ours did on twin emps till you fix your strat (or warlocks becoming more SR). Expect average guilds to clean in a couple weeks, and several likely all in the first week.
I am guessing for the casual and semi-hardcore guilds, the barrier is going to be time. The first couple of weeks, I do not believe my guild will get stuck on some particular boss, but we are likely to run from time till we have learned the fights.
It is going to be interesting to buy gold wow classic eu see. Back in the day there weren't many guilds able to realistically attempt 4H. Many who killed them moved on to clear within a few weeks, however they were the directors that motivated people to bother with planet fans. Surely everyone knew going in that they would take some FrR preparation.
Gothik has been a significant DPS check that I'm convinced we could brute force nowadays, so that he won't even register as an overdue boss.