I wouldn't mind if traditional EXP parties returned, so long as it wouldn't become the only way to level up. (Obviously it would never be the only way in this game).
As others said, even getting an EXP party was hard in FFXI. Could take at least an hour to get enough people, let alone actually get a good camp to kill everything. On top of that, if the party wasn't relatively balanced you were gonna have a bad time. Couldn't just have 6 DDs (DPS) in a group, a single mob could destroy that sort of party (because if the mob didn't check at least an Even Match, it would give like no EXP because of the amount of party members). But in XIVARR there are fate groups that can just zerg everything without the absolute need for a tank or healer (some fates excluded of course, particularly level 40 and higher level ones, plus like Svara and Cancer and whatnot).
And story time! My first EXP party in FFXI outside of Qufim worm/crab parties was in Y'tuhnga Jungle fighting Mandragoras outside of Kazham (so like level 30?). Worst experience I ever had in the game. I was a Red Mage, and I wanted to melee to help kill faster because A) it's what I was told to do in Qufim, and B) we had a WHM in party and a lvl 75 RDM healing us. But guess what? "RDM ONLY HEALS/HASTE/REFRESH!!! [derogatory remarks]!!!" That was always the response I got while on RDM (even before I was a high enough level for Haste/Refresh...).
So I switched to Dancer, which I mostly soloed up to like 60 in using Fields of Valor pages because "Sorry, already have a dancer", "Dancer damage sucks, already have a sub healer/support", or even just "No DNCs". From like 30 to 50/60 I was mostly in Altepa Desert... I hate that place so much even now.
Now I wanna resub to XI for some reason... lol. Upgrade my level 99 RDM and DNC Empyrean gear past +1 finally haha. Will give me something more to do until Heavensward XP