In my opinion they should at least try. Let's use it's #1 competitor as a baseline.
In WoW raids mattered. You actually feel like you have a purpose going in that instance and that every raid is unique. I remember going to fight Elegon, the celestial dragon and being amazed by his arena, mechanics and the extra lil achievement to boot. In FFXIV it's more like, oh this thing is here, guess you have to fight it... We are literally murder hobos. Something arrives, we kill it. Sure we do it to protect but we never actually get above that. Coils were the only decent raids that could be compared to WoW's. It felt alive and part of something bigger. Not disjointed like Alexander and Omega feel.
The PvP in WoW is actively supported. Open world PvP might be dead but the BattleGround (our equivalent of frontlines) and Arenas (our equivalent of the feast) are still really active and diversified. You can play capture the flag one game then play oddball the next swinging by escorting payloads. In FFXIV the PvP is.... suffering. Now before the PvP fans jump on me. I have played plenty of XIV's PvP, before and after the rework. It's not that I never did well into it, just that doing so felt painful. The combat system of XIV just isn't suited to it and PvP feels more like they had a checklist and PvP was on it. No actual passion for it in the development of it at all.
The side activities. That point is hit or miss obviously but the greatest contrast is Lord of Verminion. Imo LoV should of been what Pet Battles are for WoW. A Pokemon like minigame. It's silly to say but Pet Battles are extremely fun even through their simplicity. LoV tried to be complex and strategic and it blew up in it's face... Even though FFXIV has side activities like Triple Triad and PotD, it's just not enough and not updated enough through the patches. WoW has the Brawlers Guild where players have solo encounters against multiple bosses testing their awareness and their skills to take them down and get as far as possible through the gauntlet and there's probably other stuff I haven't seen yet as I rerolled on a differnet server. Tl;dr, side content is fun and varried while being supported.
Community mentality. Oh boy that's a touchy subject... You could say WoW is the polar opposite of XIV. Often seen as the bastard child full of toxicity while XIV's is a little angel making sure everyone got a chance. Well this sucks. Not everything is for everyone and content should not catter to the lowest common denominator. Not everyone can do savage raids, so why make the first 2 fights a borderline joke and just make the challenge on the 3rd out of 4? Why are EX primals so easy that a group could clear it blind in 1 hour? This is both an opportunity and a problem. Gets more people into endgame content but alienates those that thirst to push themselves. Sure there's Ultimate for the latter but it's more a matter of how much time are you willing to invest I feel. Also the community coddles the bad performers and SE encourages that! No feedback on bad DPS play. Healer and tanks getting away with only doing their basic jobs instead of pushing their DPS whenever possible. It gets so bad, that it's the players who actually push themselves that are the bad guys. I lost count of how many times I was called a tryhard for being MT and in Deliverance on EX primals. While on WoW it's the opposite but not as bad as people imagine. Sure you get the tirades that you always get of "l2p scrub", "trash tier damage" etc etc. but it's only the reverse that you seen on XIV. Except of complaining about the good and tryhard, you complain about the bad and lazy.
All in all, maybe WoW seems to have so many upsides because the team has over a decade of experience behind them by now but you see that they are not afraid of innovating and improving what is there. SE being once burned twice shy are very hesitant to step out of the tried and true method but that is slowly poisoning them. I'm not saying FFXIV will die befor elong and being a doomsayer here. I'm saying that it will start losing appeal. It can fall back on having great story and gorgeous boss fights for sure but once that initial wow factor is gone, what is there left? SE just has to take the game in a new direction, doesn't matter which and it'll show it's players that they are willing to work on the problem. That would quiet down alot of worries and bring satisfaction to most players. Until it does that though, content like Eureka (which is just a repackaged Diadem and a failed Timeless Isle clone) will just keep driving people away.