So this topic is back is it well i'll just restate again why i don't think MSQ being optional will happen anytime soon;
It requires a lot of work to:
-unflag everything (sidequests unlock as you progress through MSQ so all these will have to be updated) and add new flags based on level this will also include retainers/gc joining and thus mount unlock
-add new side quests including all translations to any content that was mandatory for MSQ we are talking 15 new dungeon(this is just the leveling ones which means context to the Aery/Vault/Doma Castle are really lost), 3 ARR primals (Mog/Levi/Ramuh), 2 HW primals (Bis/Rav), 2 SB primals (Laksmi/Susano),
-outright change encounters/dungeons/questlines why because Shiva/Nidhogg/Thordan/Shinyru/Omega/Tsukiyomi/Eureka have heavy story significance and well you either get locked out of these so thats 17 fights you cannot do without dong a massive sidequest with all existing cutscenes, fedexing that is still there which also means your locked out from all ponies/birds/dogs and their respective completion questlines their weapons etc etc (and if you think most people would go through MSQ to repeat old content they have done just to do these fights well just XD) or you strip any speech and VA in the fights or you risk spoilering story
-Flying/Diving/inn rooms/levequests/guildhests unlock changed
-Zone access changed you cannot enter the HW and SB zones without MSQ progression after all
-Beast tribes changed specifically HW/SB as they require multiple sidequestlines but also use MSQ with references especially Ananta can't exactly redecorate a bridge if Garleans still holding it XD
Then you have to ask what about all the emotes/outfits/items we get given should they remain in that long sidequest or be given to people because people will complain that they are locked behind the sidequest formally known as MSQ, and if you just lock all that i've listed then you lose a fair chunk of current endgame content
If they were to revamp MSQ to being optional then that WILL come at the cost of another potential feature of a future expansion
TLDR : Ask for the MSQ to be streamlined there are certainly places to do this but i do not think making it optional will be possible, at this stage we are going to a 3rd expansion and only now are they considering how to streamline ARR only, there will always be cutscenes in ffxiv its best to slow down and take your time or you will burn out and if they bother you so much skipping them is an option