I think the crux of the whole protagonist issue is that definitions are important. Words are powerful, but they are powerful because they mean something. If you change the definition of a word, then that word has a different kind of power than it did before. Most arguments are an attempt to redefine things, whether words or idea, in an attempt to gain something (influence, clarity, etc.).
I'm seeing a lot of people trying to come to terms with a new framework for the word protagonist. Some see the definition changing and feel as though the spirit of the idea has been lost. Others are moving with the change as it creates tangible footing to stand on. Personally, I don't think either is wrong, but there are a couple things to take into account.
The definition has moved. In fact, it has become more vague. With this new presentation, we are no longer dealing with the face of the game or the most present character throughout said game. We are now talking about any of the major players so long as they are relatively equal within the game itself. For many games, this doesn't change anything, but for some it does. For instance, if we got someone from Bravely Default, the new definition of main protagonist would now include Ringabel, even though we would otherwise assume our options would be Tiz, Agnes, or Edea. The Asterisk holders would still be off the table, presumably. If we keep hold of a protagonist or mascot first rule, then we should acknowledge that it is a different rule than it once was. Because it is.
The other point is that if we do away with the protagonist label entirely, then means of discussion will be lost. Points in favor or against certain characters will be untouchable, not because the point are nonexistent, but because the words available to express them are gone. So we need words like protagonist like we need the color blue. It might not always mean the same thing to everyone, but it does help in articulating ourselves.
Sorry if this post seems late for the conversation. I've been making lunch while typing.