Personally they need to have the same system as ffxiv and give more options on obtaining gear. For example in ffxiv you can take a break for months, and jump back right in on participating into 99% of the content as within two ish days you can be gear ready (not p2w items btw, sub based game). In terms of content, let people be lvlsynced to do x dungeon and add rewards that are beneficial to not only the geared player, but also the lower geared player. Remove the gold bidding system, change it to rng roll between 1-100 so even the lower geared players have a chance to get x item.
Other things to do, make a crafting/gathering system people can work on. I remember back in the old days we needed mats for crafting transformation stones and bots were camping spots, but it can be countered with an anti cheat system.
I think the revival of old dungeons is really good for the game if the rewards are great. Just give players more options to obtain gear as in spamming one dungeon for an achievement makes people burn out. 300 times, yeah instead of that add some of the thornwind accessories to ebondrake citadel where players are synced to minimum stats. Kind of like that poharan dungeon event.
I am sadly nowhere near the grinder anymore, 9-5 job but do enjoy your game!