First of all, teams do not have to field one Chinese player per match anymore. This change was made to try to get some teams from all over the globe to sign on and does change the balance of power in the league around a bit. A higher overall prize pool also contributed to getting some more teams into the league. Speaking of more teams, right now there are projected to be twelve competing teams in the upcoming season, so we'll have five new additions with a total of four more teams than last year. Apparently, interest from teams was quite high this time, which is great to hear.
You will note the list below is currently counting 13 teams, I could not confirm until now which one of these has dropped out, so treat this with some caution (I think it might be one of the original teams). No matter what team is out, though, we're in for some fiery team league action.
Update (20.2.2021): Cascade apparently fell out, according to this post, which appears to confirm the list of twelve teams below to participate next season.
Update (2.3.2021): The twelve teams below are here confirmed by digmouse to participate next season. I've also heard that the league will run under the title "World Team League" (WTL) and not as GTC anymore.
Dragon Phoenix Gaming
Good Game Gaming