The problem is Gold Coast and Brisbane are in South Queensland so was never a good name.
Logic would suggest Gold Coast/Scenic Rim team then an Ipswich/Logan/Lockyer Valley/Toowoomba team then a Brisbane /Redlands/Moreton Bay team.
But hey logic plays no part in these discussions, Hence St George Illawarra and WestsTigers.
Im not so sure about new teams just trying to fit into the unused space. Seems better for them to try to come in over the top of established teams and claim the same areas. (Otherwise you just get the niche teams like Manly/Cronulla stuck in tiny areas between much bigger clubs)
No team should ever just let fans go to other teams without some fight. And the competing for the same area is the perfect way to begin a new rivalry, ("this is Broncos territory" "Nah, f*ck you. this is Crusher territory", etc)
If new clubs come in and pick names based on teams that have come before, they should be trying to diminish the existing teams. EG, the next SEQLD team could come in a distainfully brand the Broncos as "Brisbane CITY" and leverage that as a "the Broncos dont care about regional SEQLD" or "NSWRL Broncos; they killed the Brisbane RL, grrrrr"
To me, calling a club "South Queensland" is a declaration that "WE are the major club here. Brisbane City Broncos and Tweed Titans are f*ckin nothing"
Fight for the same area and just establish the contrast.