I am a huge solo-er so I can give you some perspective.
I started FFXI soon after launch and was super-social, super-party, super-LS all the time. I would do storyline/sky/sea quests for 8 hours in a row or party for the same amount of time, had a static, etc. etc. It was a blast. But at the same time it was incredibly draining and did not make the people in my Real Life very happy with me sometimes.
When my son was born I took a permanent break from FFXI. I quit kabisa. It was liberating and the right thing to do for my family. Three years later, after my daughter was born, I felt like getting back into ffxi but not like before. I wanted some constraints.
The constraints were: 1) no xp partying 2) no questing/storyline blah blah until after bedtime 3) solo if possible
I chose Beastmaster and following those rules became a great BST. No I did not have Relic anything or Nyzul stuff but I poured my time into getting any soloable/buyable equipment I could like Tsar's Egg, Stout Wristbands, Lyracists Gonnelle, Spurrer Beret (favorite solo), Volunteer's Nails (2nd favorite), etc.
I list those pieces because getting them all on my own, including some of the prereq's leading up to them, was a real accomplishment. If you've ever (pre abyssea) solo'ed Morielle Mortelle or tried to figure out the spawn time of Merrow No.5 you'll know what I'm talking about. I would occasionally duo or trio with other BSTs.
Eventually I solo'd my WHM (as whm/bst) to 75 which was almost more fun than BST by itself. Then I moved to BLU/BST, etc. I solo'd full merits on my BST, mainly killing hundreds of Doom Warlocks and netting millions of gil selling Blizzaga III on the AH. Such great memories!
With FFXIV I was hoping for a similar experience but it fell hugely flat. Soloing was easy but only because of Guildleve's and company leve's not because of any strategy on my part. Anyone could solo with no effort. I eventually partied a few times just to get those last levels to 50 because you go basically get them in a few hours from a SB party.
However the party grind from instances made me sick. I watched people in my LS do Ifrit, Shiva, Moogle, CC, etc. HUNDREDS of times with crap drops. This did not look like fun to me. And because of the monotony, people were expected to join these grind-parties any time they were online because of the ridiculous amount of time it took to get anything. Out of the prime fights I did Ifrit one time and got 2 doo-dads. I remember being a total instance noob, I thought each totem could be exchanged for one weapon. When someone told me I needed TEN, I was like @#%(*&@#^???? SCREW THAT! Never went back and I was plenty happy.
The few times I did eventually party after hours was for AF and none of the experiences were good. Hours wasted waiting for people and doing 3 or 4 different fights until it was 3-4 hours past my bedtime and I needed to get up for work in 3 hours. I got all my AF but felt like it was not worth it. I turned to crafting. During the last couple months of FFXIV I got all my equipment crafts to 50 except blacksmith which I felt like I should save for 2.0 so I have at least one craft to experience the new system with.
I'm looking forward to way more solo activities, hopeful that some of the instance requirements will be 1-2 players. Most of all I'm looking forward to the auto-party feature so I can do ONE run of Ifrit and quit without feeling bad - or without waiting hours for people to join. I just don't have the time for that anymore, I have a family of SIX to take care of!