I will give you a very simple answer on how to fix raiding for majority of ppls enjoyment..
Make it easier, the reason why Final Coil was the best was because of the story, encounters, and the difficulty. Ask yourself one thing, is it really worth all the stress to raid content for 2-3 months and when you finally clear you get to do it all over again 3-4 months later. Make it easier so ppl can clear in about 1 month and actually can afford to get loot for alts while the gear is still relevant and not just for glamour. Don't bother telling me to find very talented ppl, its about playing the game stress free and for fun tbh. If you want to cater to the hardcore ppl make something similar to savage second coil where you give them a goblin mount if they clear it or w/e. Point is make it easier so more ppl can enjoy it. Attack my opinion however you want, I believe in what I said and I think it is a solution to current raiding issues in the game.