That poll was during Heavensward during the entirety of which Black Mage did have a significant issue with timer maintenance, and its player population dropped. It says nothing about Stormblood Black Mage, however, since all of the real HW issues went away in SB. The Enochian timers in Heavensward were horrible because there was a very real possibility that your dps would be cut in half for potentially 30s, and it was easy to do this if you didn't know the fight well. That was the complaint about Black Mages in Heavensward, and one that they have now fixed in spades in Stormblood. Not only is Enochian ridiculously easy to maintain now, even outside of combat, in the rare case you do lose the status effect it only significantly lowers your dps for 18s at most, and even then only if you lose it specifically at the 12s mark after hard-casting it which takes a special kind of effort to do.

You also keep talking about how Black Mage is the only job that requires so much more extra effort compared to other jobs, because they have to know the fight better than other jobs. That's a rather hilarious statement. Just as one example, MCH has a very complex and high-precision required rotation that blows Black Mage's rotation out of the water in terms of difficulty, but still also suffers from significant dps loss for making a mistake or having your rotation interrupted at the wrong time by not knowing the fight well. Your entire premise for Black Mage needing to be reworked is based on the very narrow concept of "I don't do well with turret style gameplay, therefore Black Mage gameplay needs to be reworked." If I were to follow your thinking, my statement would instead be "I don't do well with priority based application of oGCD abilities at high speed, therefore Ninja gameplay needs to be reworked." I don't, however, say that, because I am fully aware that there exist many other people who are are far more than capable at succeeding at the job than I am, that there are multiple jobs that do work well for my gameplay strengths, that my gameplay weaknesses don't need to be catered to across every single job, and that just because I don't do well at something it doesn't means that it is not good design.

The final thing I will say is that you do come across as misinformed about BLM gameplay including even aspects of some of its basic mechanics, and how well it functions as a job overall. Sure there could be tweaks here and there (e.g. the whole thing about selfish dps vs. raid utility dps is a whole separate conversation) but that's something you can say about any job. It is sitting in a good place right now. E.g. Its single target damage is ridiculously high. On one practice dummy I can pull numbers that eclipse all the other caster jobs by a huge margin, and in practical gameplay where movement and interruptions inevitably happen this dps lead is only lessened not lost. Even if I'm not familiar with how best to do the fight as a blm.