I don't really see how
Just announce it the season before that next season the top 64/32 leaderboard sparrers will be accepted, just like the GST
I'm sure it'd be even easier than hosting the GST

They'd only have to amend the GST bracketing system script, I know it wouldn't take too long to do that
It's probably just a matter of someone not having the time/desire to host it and everyone else being too uncoordinated to do it properly