Is FFXIV viable as an MMORPG without doing end-game & raiding?

[Ryel]

Without "endgame" would FFXIV be viable as a subscription based MMO?

I don't think it would be, no.

However if this were a B2P game supported by it's cash shop like Guild Wars 2 then yes I would say it's model would be very viable, even preferred with this games patch release schedule.

As mentioned by another poster in this thread the majority of the content you listed can be broken down into a few categories; either it's done once and once only, its done simultaneously with other activities (as in done together to complete common objectives, see: leveling), isn't available for all players equally, or isn't really supported enough to be worth doing all that often due to either lack of DF / matchmaking support, proper rewards, or the fact that it cannot be done while taking part in other content.

A really light and not so detailed shortlist would look something like..

Content done once and once only:

MSQ
Most quests
Hardmode (story) Primals / trials

Content that can be completed either simultaneously or in parallel:

MSQ
Majority of sidequests
leveling jobs
dungeons
FATEs
Relic (after MSQ obv)
Guildhests
Hunts
Levequests

Content that is limited in accessibility:

Housing
Gardening
Chocobo stables
Company airships

Content not supported in a way that makes them fully viable activities:

Lords of Verminion
Triple Triad
Chocobo racing
PvP (Your mileage may vary)

Keep in mind that isn't to say that stuff like LoV and Chocobo racing isn't fun because personally I enjoy both on occasion, but if nobody is really doing either or refuses to play with others (win trading queues) because there's no proper system implemented that allows you to play with a greater pool of players I can't really count them as viable pastimes.

This means that at level cap the content that is designed to be done repeatedly and thus keep your sub going is the content that continues your character progression, which is mainly Ex Primals and "Raids" (SE's definition of raids would include the crystal tower and void ark series in this but going by your post i assume these are excluded) AKA Coil when it was relevant and now Savage Alexander. They obviously have tried methods of releasing alternate ways of achieving ilvl progression at cap with things like Diadem and adding Eso upgrades to Hunts and VA but they're always released as a supplement to raids or they'd be introduced at the start of the patch and not at the end.

The overall player response to the latter part of the 2.x series (when FCoB was on it's 8 month stretch) and the majority of the 3.x series has supported this idea thus far.

If you are a brand new player or are a player who never really reaches level cap (takes a long, long time to do so) then sure it looks like a wealth of content is available in the game, however if you're a player who continuously makes moderate strides and headway (keeps somewhat current), then what initially looks like a wealth of activities slowly begins to dwindle down into not many things on your plate. Additionally if you are a player who actively avoids endgame content like Ex primals and raids you have the fallback of constantly telling yourself that "there's plenty more to do!" because now there is an entire section of content you're just refusing to touch which you tell yourself you can chose to attempt at any time in the future, If that content wasn't there however (say if they removed Ex primals or something) the pool would begin to look much, much smaller.