It's really not just gear. Early into Gates of Discord they nerfed charm VERY hard within that expansion. A ton of guilds could not actually complete the ikkinz trials afterwards and would literally beg for help from people who had done it. That attitude carried into omens, where they refused (not just forgot, refused) to update ae stuns so that they would phase out on top of hard nerfing charm. Enchanters in god/oow basically ate all the nerfed that the many tlp churners who always quit by then ask for, for their earlier eras. Tons of enchanters bled more than usual bleed because of wow launch and there was a lot of bitching during the latter 70s and 75s expansions about how they needed to make a reason for enchanters because nobody was playing them. On tlps, it happens again on the replays, and enchanters vanish in these eras.
Caster balance is atrocious in the 70s. Non-necros are still pretty bad in the 75s. It's not just on raids either - the entire design of these expansions is laid out so that if you are a random wizard you can no longer feel useful. Soloing c2 tables for xp is just not going to carry you. There isn't really anything for casters to do without joining a group, and groups really don't want casters as much, and the idiots in charge of game design at this point in eq's life (pre-sof) had this boneheaded notion that because casters could solo they shouldn't be as good in groups. It's a bad downward spiral that leads to very few caster mains and almost no caster boxes. Guilds become heavily concentrated. It's super noticeable in DODH where I've heard from every friend I've talked to who made it there, and the couple I was in there, silk rots ASAP. The balance issues aren't fixed until sof and by then it's hard to expect "new" casters to show up.
The tank situation also becomes more and more pronounced in these eras. Pets aren't REALLY viable before sof for the role and mercs aren't until sod and never really all that viable either. You will hear people talk about rangers being ideal tanks for classic leveling. For god+ you use a plate tank if you want to do real baller shit. There aren't good substitutes. Meanwhile, the stuff you kinda need to do becomes more important, so you are both more reliant on tanks and less capable of getting by without doing the shit that needs tanks.
