The idea that unicode proposals have to be submitted to the unicode consortium is trash. It's be better to declare parts of the unicode standard open access (like the 2.4GHz wifi band) and just let people exchange/trade emoji sets.
“[Unicode] brings order to a chaotic state of affairs that has made it difficult to exchange text files internationally.“ [0]
If it's not the Unicode Consortium who decides, well somebody has to.
And what is my phone supposed to display when it gets an emoji from one of these sets? Is it supposed to have a URL that it downloads them from or something?
The whole point of Unicode is to be a standard of communication. So it's hard to see how a free-for-all of characters or emoji is still a standard at all.