It's admirable that you went to such lengths. And of course people improve in certain areas, simply through getting used to the oddities of 14 such as snapshotting. But you'll appreciate that the fact you were able to do this does not mean most people can.
Let me give a recent example. I did M1N. I died a lot. It was apparent I was "wasting the time" of those players who are more skilled than me. When I looked at a guide for M2N it was clearly much harder. I've chosen not to attempt it, and that is absolutely fine. It's not required content. But there isn't a magic wand I can wave that will allow me to participate in such duties without being a drain on the rest of the party. One cannot put a "challenge" earlier in the game that will alter my neurobiology.
Similarly, Duty Support/Trusts gets a lot of flak here because it allegedly simplifies dungeons, much to the annoyance of many players. But here people like me can actually practice and learn fights without inconveniencing players. And I can tell you what is learned is like ballroom dancing. My reaction speed and ability to read tells in general doesn't improve. They are capped. I can however learn how to negotiate that particular fight.
Ironically, I think a significant alteration in ilvl synch would provide a sort of solution to this more general problem, simply because it would gate 14 at a much earlier part of the MSQ and people would simply quit, thereby allowing the game to be harder for the survivors. But that is not an approach SE will ever take, hence my interest in solutions that are not fiscal suicide.
I bring all this up because these discussions have been going on for years, with independent camps demanding incompatible changes from the devs, then blaming each other when nothing improves. We need to find a different path.