Interesting. There was talk of this when the articles in the OP came out, but this is the most concrete reference to GSP possibly starting a fighters union I've seen.
That said, I've already seen some sources indicate that this is premature, false, a hoax, etc.
Will definitely be paying attention to this.
I wonder if GSP will come up against any resistance from other fighters, given his stance on PEDs/drug testing.
I also wonder what a union would mean for the sport. I think it would be good long term, because salaries would go up, attracting a higher level of athlete, but I wonder if that is overstated sometimes. These guys don't go into the sport to be a curtain-jerker or gatekeeper; they think they will be the best, and right now, the top guys are pretty high profile. I'm also not sure how the fighter vs. athlete breakdown would be affected.
And in the short term, from the fan's perspective, I don't know how it would change things. The UFC has some questionable tactics and policies, but they've generally done a pretty good job of giving the fans what they want. I'm not sure how a fighter's union would affect that.