the main issue with rgl was the admin discretion when it came to punishments, and even that's seen improvements over the course of the season (imo). I have faith that it will continue to improve in this aspect as the league matures and the admin team gets more settled in.
Additionally, rgl also supporting other formats helps with the potential longevity of the league, even if 6s player numbers decline. nacl might not be able to continue running a league without a certain amount of players, but rgl is sustained enough by HL and 7s that it wouldnt matter. (For the record im talking about longevity in the same way b4nny is with turning tf2 into an esport or whatever, i just think rgl is less likely to go the same way as esea did in the near future.