The fullbringers were handled better then the vizored and it made sense to introduce a bunch of them. The plan was always to make them the villains of the arc and each one introduced gave us the chance to have a one on one fight with a fan favorite character when they returned at the end. The vizored should have been antagonist, and them training ichigo should have lead to them being actually allied with Aizen and have them be killed off by ichigo and captain team to defeat in one on one fights. Then when the arracar stuff got underway it would just be ichigo and captains we care about vs arracar.
Without turn back the pendulum there is literally zero reason to care or like any vizored who isn't Shinji. Even with it I still didn't care about most of them despite how well written the flashback was. Kubo never did anything meaningful with the characters outside of training Ichigo so they might as well not have existed at all.
The fullbringer arc was the lowest point of the Bleach Manga, just nonsense all around. So it doesn't matter if Kubo did what he set out to do, it just means he set out to include a bunch of unnecessary, flop characters no one could possibly care for and succeeded.
The potential of the Vizard alone and what could have been done with those characters is way above what was done with the fullbringers, even your proposed Vizard plot proves it.