This right here. I had a blast leveling until around 30-35 collecting spells as I go. Fighting much higher levels with my chocobo in order to learn their spells was fun too. But once you get to about the level range previously mentioned, it becomes a boring slog of spamming 1000 needles and being carried through dungeons/trials over and over to get a rare ability drop.
Basically, blue mage just loses its flair at mid level, and at that point is where people (like me) felt the need to power level. Usually I don't do that sort of thing. I love enjoying content without speeding through it. But I just couldn't. It got so boring and tedious. At the very least, my partner and I focused on lesser known areas and never intentionally stole other players' kills. I also helped other blue mages by switching to a tank class for awhile for mobs like Dalvag and such.
Now at level 50, the grind is even more abhorrent. I feel absolutely useless as a blue mage in these trials, because our damage output is piss poor. We get a few combos, but none of them work because they focus on certain debuffs that bosses are immune to, so the added potency doesn't activate. Can barely tank trial bosses either - their tank busters laugh at mighty guard. Best thing a blue mage can do is spam white wind all day while running around in circles while feeling terrible about being the weakest link in the team.
And to top it all off, the RNG for these abilities is absolutely insane. A full team of blue mages will barely survive most hard trials while taking a good 10+ minutes to defeat it (Why the hell do we not have LB's!?). The droprate for abilities from these bosses is so damn low, it can take hours just to get Ifrit's. Seems the best way to deal with it is to have one person switch classes and carry the team; typically a red mage. But that person doesn't get the drop IF it drops. So the cycle repeats again for this one poor soul that sacrificed their chance to succeed so everyone else does.
Then there's the EX primal abilities....oof. I don't think I'll be getting those.