Now I played some FFXI back in the day and went through that same experience you just described. I don't recall anything memoric about it, nor would I call it a pilgrimage. Frustrating is a bit of a better word. I did it all solo up until the dunes so my experience wasn't exactly the best. And even then it wasn't exactly great. Just like in FFXIV, there are a lot of shitty parties out there that make you not want to party ever again.
Again, good players will do what you described. Good players will look for ways to be more useful in a group setting. Good players will build up their skills. Bad players will do none of that, regardless of how they level. Likewise, good players will do all of those things regardless of how they level.
Though my leveling was quick I still felt a sense of achievement upon completion. I still looked forward to every new WS I got. I thought of how those would make me better. That's because I'm a good player. Bad players will do none of this.
I will, however, agree that leveling could be slowed down a bit. Not to FFXI levels but I think maybe 3 weeks to a month from 1-50 is reasonable enough. 45-50 shouldn't take hours. The 1-25 range is so quick that we don't get to make use of Shposhae or any of the lower level content.
Again, good players vs bad players. If you make a game challenging, good players will rise to the occasion. However good players will also better themselves without the need of a specific challenge. Good players will take the time to help others if they need it.
I've had people say the exact thing about the community (in-game) of FFXIV. We've had people join up in our LS who have told me that they love how the sense of community is coming along in the game and how it's still so much better than most MMOs.
I would have to disagree with 100% NEEDING a group to get anything done though. It should be an efficient way to get things done, a better way to get things done and should really only be 100% required in end-game. This game was designed for a more casual audience so things will keep going in that direction. An emphasis on both solo and party content being viable means of making at least some progress.
This is more of an issue with lack of content due to the game being rebuilt from the ground up. We'll have more things to do in time, just need to be patient. Also people currently ARE willing to PT up a lot of the time for XP.
PL doesn't make you a bad player. Leveling "legit" doesn't make you a good player. Personal motivation to be better at your role makes you a good player. I've leveled some classes legit, I play them well. I've had some classes PL'd to 50 and I can play them well. There are many people who I've seen level "legit" who have absolutely no idea what they're doing at all.
Leveling is part of the journey but it shouldn't be the major experience of the game. Interesting mid-game content would be one of those things. Honestly though, I've had more enjoyable experiences and fond memories solely from end-game than I do from any mid-game content or leveling. In fact almost all of my bad experiences with FFXIV are from leveling groups. I share memories with people that I like playing with, pretty much my LS. Didn't have to level "legit" to get them. I feel we have a good amount of comradery going in our group and some of us PL'd.
I'm glad you had a good experience, however you must understand that you are in the vast, vast minority there. I think you're the first person I've ever heard tell a story about enjoying a long leveling party. Pretty much everything I've ever heard, along with my own experiences, has been negative. Part of the reason I don't do random groups or anything really outside of the LS is because of this.