My opinion is that WoW itself started out great. Not only did it build on the already successful Warcraft games, it launched with a huge game world that took itself fairly seriously and had multiple different playable races each with their own starting areas and lore. It was also a lot more accessible compared to earlier MMO's, though still committed to having an open world that could be dangerous. I have fond memories of getting lost by going in a random direction, exploring a cave and discovering 'secret' quests. It managed to maintain my interest until Cataclysm, which incidentally was the same expansion that streamlined the base game's content, removed a bunch of quests and reduced the danger in the open world to make enemy encounters very easy.

To me, FFXIV is currently the best option on the market as far as I'm concerned but that is largely due to the lack of competition. It isn't really threatened by anything right now - especially when it comes to being story driven. ESO has a bigger open world with more things to do, but the character models have an 'uncanny valley' angle to them in my opinion...and the combat is jarring to me.

There's a lot about WoW that I like better, but not enough for me to continue playing it. The main things I miss are some of the playable races such as the Blood Elves who I adored both in terms of their character models and the lore surrounding them. I also miss some of the classes - Death Knight, Warlock, Druid and Demon Hunter in particular. Reaper is coming with Endwalker and looks promising, though hopefully it is written to truly be a 'darker job'.

All in all, I think there's a lot of elements that both MMO's could take from each other moving forward.