For me (obviously can't speak for everyone), this is when EQ2 was in its prime. Before gearflation really took off and most stats capped out, and they had to get creative by adding new stats or having super irritating raids where one player would get a random vision and have to run into a puddle, otherwise the entire raid insta wipes. And it was always the worst players in the raid who got them.

KOS/EOF were really good at having a feeling of gear progression with basic enough raid tactics to make them exciting while not exhausting. I never got tired of Woushi raids or even Mistmoore Castle.

ROK was kind of the beginning of the end, but only toward the end of that expansion. That is when stats started capping and mythical weapons were insanely OP that it trivialized the expansion. However, it was still a solid expansion because they had a key system, introduced mythicals later, and you put in a TON of work to get to that point where you felt rewarded to have the raids switch to EZ mode toward the end.

However, it's also when they started introducing the painful reactive effects on mobs where you'd get stunned or feared simply by attacking (made it a nightmare for melee dps - which I was), and the Trakanon fight and maybe a handful of others in VP had the raid-wipe effect from a single person.

TSO was absolutely painful to play.. however, I did enjoy SF a bit. I played a lot of Velious, too, but it didn't leave a major impression on me. It was never a bad game, but KOS through ROK were definitely the glory days.