I recently started sparring again today. Pretty rusty, and my phone has a bit of a latency...
Back on the topic, I think players would get frustrated sparring others from other countries. The server update helped mitigate some of the issues but others still have an awful ping. I think if there were 1v1 tournaments, they would most likely need to be segregated regionally to help accommodate for that issue.
"But GST is fine how it is! It wouldn't be much different."
And there are always times when you get screwed by some lagger from another country. Not always, but it does happen.
But, chances of hitting players in a GST are higher for sure.
It's possible to not even be able to hit because of ping, and that's happened to everyone before I'm sure.
It's just annoying, and it forces a playstyle that stalls the match. 1v1's would be kinda tedious.
That's my take on it anyway.