I think the G-leage in general will be fine... these farm teams have existed for a while, and they serve as good leagues for NBA teams to develop players. The Houston rockets routinely send it's young stars to it if they are struggling, and will then call them back up when they are doing well. It also gives smaller 3rd or 4th rate cities a chance to have some sports and maybe catch some future NBA players.
The problem though, is the G-League Ignite, which is specifically designed for Highschool athletes to go to instead of college. I'm not sure all the details here, someone else can fill them in.. But what I do see is a LOT of failed Ignite players and busts (OTE is another league), kids that probably should have gone the college route and not try to play semi-pro ball against 30 year old journeymen.
You have guys like Hardy, Nix, Scoot Henderson who are just not very good.. then you have some guys like Jalen Green and Kuminga, who are starting to come along in the NBA.. but still far off from their ranking. The Thompson brothers this year.. look decent. But nothing great in my eyes so far.
It seems to me that almost every HS player who opts for the G-League, gets exposed pretty badly.