Because it was, nothing you've mentioned is outside of what I mentioned in my tiny tiny priority list. That tiny tiny priority list is absolutely correct in how you played the spec. There is nothing complicated about maintenance, which is all the spec was. Adapting to trinkets was literally just pressing soulburn -> soulswap when your procs happened, which you used a tracker for. And then following up with haunt.
And to make matters worse, affdots even trivialized the need to know how powerful 1 proc was vs another, to the point where literally anyone could pick up the spec and play it to its max potential without needing to know much of anything about the spec or need to learn much about the fight to adapt the spec to it. It was actually braindead easy to pull off if you knew how to set up a buff tracker or just downloaded affdots.
I'm still waiting for what was difficult or complex about the spec, because I'd genuinely like to know. I've given you the entire priority list on how to play it already, which again is correct. So I need you to provide me with the secret strats that I apparently didn't know the entirety of mop.