There's a follow up post from Ion.
Says he uses need before greed in his guild which, yeah, is weird as fuck. I can almost guarantee most serious or even semi-serious progression guilds don't. Design done in a bubble.
The main thrust of the change is to avoid ninja-looting/reserves/etc. Which is a noble intention, but they fucked over a subset of legitimate players at the same time. They believe the benefit outweighs the cost. I don't necessarily agree.
Personal loot needs to be a better than it is now, or there needs to be a new loot system that works even better. Ideally something that allows targeting of specific pieces beyond the current bonus roll system.
Still doesn't address single drops like Mythic mounts not working when personal loot is enabled, and if personal loot gives out the actual tier piece rather than a token, it's hardly as effective as master loot for targeted gearing, even if it is tradable.