I would set it out like so:
<<1 reset per week>>
Naxx: 2 months
Ulduar: 3.5 months
ToC: 2.5 months
ICC/RS: 4 months
The double reset has to go. The server was a covid baby, when people were locked down and had unlimited time to waste. Now that things are getting back to normal, sacrificing 1-2 days over the weekend to raid is a no go for most people. Alts are meaningless too as keeping them updated is adding even more raid days to an already stacked week. It's a ultimatum, it's impossible to remain competitive by skipping a reset. Buff drop rates slightly and you'll get a healthy server that will have actual player retention as opposed to people burning out in naxx from all the raiding.
Speaking of Naxx: it was, by a large margin, the most popular tier. While fresh, Naxx peak times were nearly double the numbers of ICC peak times. It's easily accessible and extremely easy to run through, even for pugs. I think 2 months or mayb 2.5 months is enough for it if it's not released literally on day 1.
Ulduar bosses were fine imho. Buffing boss HP and tank damage is an extremely lazy approach as it is. Look at the meta, 3-2 HPalas per raid, no warrior tanks.
There is 100% nothing wrong with BV tanking on Anub. It worked on retail, I fail to see a reason why it shouldn't here. In actual fact, solo BV tanking is harder in some ways. You need a competent tank, mindful healers, coordinated shadowstrike stunners etc etc. Remove it somehow, and all you will do as add an extra offtank and aoe adds. Big whoop.... the boss is easy regardless.
While double reset is reason enough not to play again, double ICC ID would be the final nail in the coffin. It is simply too long as it is. In it's current state, most guilds spend 4 days a week in ICC over 2 resets. Imagine adding another separate lockout... Not to mention I'd love that heroic ID, where people will be hardwalled on LDW :D There is only a handful of guilds that attempted it pre-buff and actually killed it, most guilds get LoD before they kill LDW. I do agree that the buffs come out way too fast tho, they could slow down a bit