I just leveled a brand new character. It was a breeze on a starter server and with the pre order earrings (I started last Sunday and reached 50 on two jobs yesterday). But...
... the MSQ is painful. Actually it's horrible. And that you're forced to do it to unlock Heavensward is even worse. Don't get me wrong, the story of the MSQ is - for an MMORPG - ok, at times very interesting (I prefer the Primal storyline over the Garlean Empire thing). The quest types and nonsensical stuff you have to do is not. There are several underlying issues I am sure a lot of people have already mentioned but I will get over my biggest gripes with it:
1. Too many filler quests. The MSQ is full of useless crap quests. Oh, there's a primal we have to fight? It's very urgent? Nevermind, first we have to do a dozen quests revolving around the banquet (yes, it's to prove your worthy to fight Titan... *sigh*) and get the perfect wine for it. This gets a bit better at higher levels but it's still absolutely unnecessary.
2. Too many talk-deliver-talk quests. I don't want to know how often Person A sent me to Person B to talk two sentences and then I have to return to Person A. It's talk-teleport-talk-teleport-talk. There are so many quests that follow this scheme and they're just horrible to play. I spent more time in the loading screen during those quests than with the quest itself.
3. Dungeons / trials requirements - I understand these things and as a healer I got instant invites until the level 50 group quests but as DPS it's annoying and I can understand frustration towards it. Nevertheless it makes sense story-wise but isn't very well done in the end.
The MSQ hasn't aged very well. For modern standards it's horrible when you're honest with yourself. 1 + 2 are 95% of the problems I'd say and especially for new players this might be a reason to quit FFXIV even before reaching the awesome expansions.