Having read your post I have a few counterpoints, which I fear may never allow for true unionization. I once wrote down my thoughts on what you have said. I would like if you would tell me your take on what I perceive are the limitations.
Here's the thing, every time this 'Players Body' thing comes up:
Let's take a sport X. Now the players of the MLX form a collective bargaining org/union. For this union to have any sort of bargaining power they need to have 2 things: 1 unity in that members will not defect/defy the diktats of the group, 2 they must have something to bargain with. Such a system can work very well in regular sports where not only can a separate League be created without the MLX if the players leave but also that the players have enough power to bargain and have a marketable talent that does not need the approval of the MLX governing body.
Here is the issue with this happening in LoL- let's start with 2. In a regular sport everyone has access to the game. You buy the equipment and go play in your local field. For it to be done professionally you need more capital for stadiums, broadcasting, salaries etc. But as long as you have the capital you are free to set up an alternate League. If nothing else many player can make decent buck training top teams of nations/colleges/schools or just teaching locally. This privilege does not extend to eSports. LoL the IP of Riot/SC2 of Blizzard/etc using this for a professional League would be pretty impossilbe without the company's consent. In many games the ToS allows them to choose who gets to play there game or not. That combined with little/no paid coaching positions means that there goes your ability to make money of LoL if Riot chooses not to include you. So no pro can ever reasonably just leave working with Riot. If Riot chooses they are within their rights to prevent certain individuals from even streaming. In other words, any pro LoL work needs Riot's consent. When you further add the transient relevance of any one game, whose skills aren't guaranteed to transfer to the next game this problem is further compounded.
As for 1, it is almost impossible to believe all the pros will work together. Not only are their personal differences but people are in a different spot in their careers. Someone like Bjergsen probably has more chips than a first time LCS rookie who is just happy to be there. No way in hell that guy risks everything to negotiate with Riot. And that is ignoring personal situations, countries and visa issues, and a million other things which make people different. There are hundreds of high-elo players who'd give anything to be pro so this group would still be to take the terms Riot offers. Korea has shown that even if a bunch of pros leave the scene goes on.
In other words I just don't see any pro union for any eSport, without someone actively pumping in resources to alleviate these concerns. Just doesn't seem possible.