The whole discussion goes the wrong way.
A roster bloating or not does not matter.
GLs are unbeatable basically in 3v3 especially for non GLs - no matter if you throw 10+ teams on them nothing will happen vs most of them.
The MM algorithm should be hardcoded GL vs GL and not allow some "tuned"roster without high clones/padme to simply autowin GAC. Because that is all what is happening.
The MM for GAC + TW is really bad - point. Be it sandbagging at finest which ends up in 200 GLs vs 50 GLs (seen this), or be it 4-5 GLs vs 2-3 GLs its in the end just very bad matchmaking.
In race car championship no one drives F1 vs GT class, but this exact thing is happening here. And people defend it only because they get full free wins - nothing else.