Most of his points are in the summary at the bottom. The marketplace by itself completely messes everything up.
I joined the game a few months later, but from what I understand, players were stuck at a limited equipment range implicitly because of the upkeep system, and could only improve by the slow progression by their attributes and in-game skill. Not many players could afford equipment that was too expensive. He proposed tying in what equipment you can wear with a wealth attribute stat, and completely rework the multi and upkeep system to something more reasonable that revolves around his proposed system.
Right now, his complaints are only relevant in the broad sense of character development. The situation we have now is similar to the old problems we had before (almost unlimited equipment, people mostly just leveling up/grinding). Even so, at the base level, I somewhat disagree with the linear relationship between equipment price and effectiveness.
The heirloom system combined with the marketplace, armory, and valor system now affects the progression of this equipment axis. Respeccing + marketplace also guarantees that you don't need to fully give up your character attributes, too. Nowadays, most people can live with any preferred +3 set, and people are free to level as much as they can. People are close to their ideal setups, so build and skill differences are the only differences with not much development left.