I quit shortly after PoP a bazillion years ago. What expansions after PoP were good? Were there good raids post PoP? Any other features or content worth noting? Thanks in advance.
By and large, raids only get better following PoP. Scripting starts to become more prevalent so its less 'stick the boss in a corner, fight him while dealing with AoEs and adds' and get some more interesting tricks to them. Nearly every expansion adds something additional to the game beyond just more content that improves QoL. The biggest one following PoP is The Serpents Spine when Out Of Combat Regeneration gets added, that substantially reduces the downtime in the game.
In my opinion, raiding peaks around Underfoot. After that, complexity continues to increase to the point that you have to memorize a ten page script for some raids, with four phases, each of which has six subphases, each of which has its own emote compliance, movement requirements, spell requirements, etc, etc. At some point, for me, it just became tedious--especially as a raid leader having to shepherd people through it all. That said, I haven't raided the most recent three or four expansions, so maybe it's improved.
It peaks in complexity and annoyance in VoA, particularly with The Triune God. Starting in RoF, it backs off a bit and you get more options for ignoring mechanics if you have DPS or following them if you don't. You also get more chances to do raid events in special ways to get extra achievements.
My Gates of Discord guide has the general flow for all the raids in the expansion (how hard they hit, spells used, adds, splits, etc...). Feel free to look it over to get a feel for the expansion. Ikkinz, Uqua, Inktu`Ta, Txevu, Tacvi. They all had their own character. http://www.raspersrealm.com/Everquest/GoD/