This is always an interesting subject because the anti-ML players love to frame ML as an "objectively bad design." As if it's somehow objectively a bad thing that some players in some guilds may like to control how loot is distributed from the raid. Like, I get it. People want participation trophies and PL is the fairest way to ensure that people are on a level playing field. And it's probably 100% correct that PuG raiding is much, much better off with PL than it ever was before. But to pretend that the status quo the game operated under for almost two decades is "objectively bad" is, well, a genuinely bad faith argument. There are pros and cons to both systems; Blizzard obviously made a pretty clear choice when they decided to eliminate ML and Group Loot seems like a half measure to kind of give it back. I can see it going two ways from here:
Scenario A: Group Loot returns, players respond well to it and it become the de facto loot paradigm for PuG raiding. At some indeterminate point in the future Blizzard returns ML for guild runs.
Scenario B: Group Loot returns, players turn it into a fuckery mess with all sorts of weird ass loot rules in PuGs and suddenly loot drama skyrockets. Blizzard says fuck it and returns us to forced PL cuz ain't nobody got time for that shit.
My hopes are that it plays out in Scenario A but I can easily see it going the opposite way as well. Either way, I'm glad they decided to at least try something, even if it's a half measure, because a world where Tier exists with forced PL is honestly not a world (of Warcraft) that I'd like to be in.