As someone who experienced both throughout my WoW career I would be still in game for ML to return in some form.
But not as an alternative to PL. At this point you cannot just bring ML back, because then guilds will opt for that and PL will only really see use outside of guilds.
What they can do is what was suggested here before: Loot would not be locked for trade, but instead you’d get something like a pop-up saying “you’re about to trade this piece of gear away. Are you sure?” and if you click yes, the loot can be traded between participants from that point on.
In the end there isn’t a good way to go about loot distribution because of human nature. With personal loot you have plenty that just goes to waste, and it makes both you and your guildies feel bad (especially if they keep the loot drops low). With master looter you get better loot distribution, but the decisions of the loot council are bound to make someone upset sooner or later.
Everyone perceives loot quality differently. I personally had someone call the council out for unfair loot distribution because the loot drop he got was only a minor boost for him, but it was a major boost to someone else. You will never be able to please everyone.
But whatever the case I feel that some form of blend between PL and ML is preferable, because as it stands right now raiding feels bad in a sense that there is loot you will not be able to do anything with (and unlike before you cannot just disenchant it to get some value out of it) and the best way to circumvent this is to get as much gear from M+ as possible, so you can feed gear over to those who do not have this as an alternative available.
The single biggest issue I feel master looter always had is that it brings along with itself a lot of administrative work and background knowledge of every class to know roughly what each needs. It is a lot of hassle most guilds would rather not go into, which is another reason why PL is much more popular: RNG determines who gets loot and who doesn’t, no need for you to think, debate, or ruffle feathers by making decisions.
Keep in mind however that my approach to raiding in wow is closer to high end (mythic) than what the majority has. I consider gear as a piece that belongs to the raid and should be distributed to the one who benefits the most of it (you die together, you kill together and you gear together).