My 2 cents on leveling / questing / boosting etc, after more than 3 years away.
Last time I played, started with a MRD/WAR, and though the job felt fun/powerful even early on, I got to ~ half way through the ARR MSQ (I think) and really started to struggle. Anyways, short version, I story boosted to the end of Heavensward, and Job boosted the Warrior to 60. I realise the MSQ has been somewhat streamlined since then, but I've watched the story through to the end of HW on YouTube, so I feel pretty well caught up in that regard. No regrets.
Realised soon afterwards I didn't want to play Warrior anymore, leveled some other jobs into the 30s/40s, couldn't commit to any of them (50 RDM incl.), and then quit. Finally wanted to mention that PoTD/HoH for me is just not an option. I've tried it a couple of times, and never want to set foot in there again. The fact that it even needs to exist is an issue in my view.
So, this is what I've come back to, and determined not to spend countless more hours futzing around on low/mid level jobs trying to decide which one(s) to take to cap first. I've spent hours on YT, watched nearly all of WeskAlber's leveling series, among others, and finally settled on PLD / WHM / NIN.
Even with the Armory Bonus + 30% Novice Ring + Food, leveling pace (FATES) really starts to bog down in the late 20s, but it's fine with WHM obviously due to fast dungeon queues. No way I was going to start from scratch with the NIN, especially since my MSQ is already complete to the end of HW. Also a little concerned about my ping, but given that oceanic server(s) are on the way, I really wanted to find out what the NIN felt like with (nearly) the full toolkit.
Boosted the NIN to 70, and spent a good few hours on the dummies, in the field, keybinds/bars etc. Finally got some muscle memory happening, and memorising the Mudras/Ninjutsu combos, opener etc. and then it all finally clicked. Holy shit, this is just the most awesome melee DPS class I think I've ever played in an MMO. The ability effects/animations/sounds as things go off are just amazing and feel so impactful. It has a quazi-ranged side to it that adds even more flavour. No idea what it was like before the latest re-work, but I'm in love.
Couldn't have possible guessed it was going to feel this good, even after all the research I did. Equally, I could have hated it I suppose, and after running through some lower level content where several abilities go missing, it really feels quite different and just doesn't flow the same way. At worst it would have been a few dollars lost and a ton of time saved.
Probably boosting a PLD next at some stage, but I'm going to keep spamming dungeons on the WHM, so I get to see them all, and re-do all the big fights. When I finally get the WHM to 60, I'll share around the remainder of the MSQ to 80. And then there's also the Trust system from 71 to 80. Apparently pretty good for leveling as well, haven't tried it out yet.
To borrow from Gordon Gekko... Boosting is good. Boosting is right. Boosting works. Boosting clarifies, cuts through, and captures the essence of perhaps your next favourite job. I also really like how seamless Level Sync is in this game, another helpful tool. Just wish that FFXIV had something like the Class Trial in WoW.