I'm not suggesting it's great content but here's what's kept me logging in:
Leveling OP or core classes to 50
Unlocking all classes (and playing the storage game with quest drops leading into class specific gear that may or may not be bis)
Testing out the meta builds (enc charm, bard ddd, this week testing out ranger)
Going down memory lane and visiting places you haven't been in decades (ymmv depending on when/if you played original EQ and/or emu's)
Unlocking races and finding ways to maximize factions
Even if you don't play Pal or SK, the Fiery Avenger and Torrid Corruptor quests
Other class quests
None of us are the same gamer we were 27 years ago but I spent literal days in lguk so it doesn't feel that bad to knock out a 20-35 leveling session there in a handful of hours.
Part of the allure for me with EQL is that I didn't get to do everything in the original EQ. Whether it was my guild's mid tier power level, spawn competition, or just lack of time to really grind a camp, I still feel a sense of unfinished business in EQ. I did everything there was to do in WoW for the first handful expansions so that feels "complete" to me. WoWF may be a superior re-imaging of a classic from my younger days but I just don't feel the pull for it as I do for EQL. Something, something...you'll never forget your first.