IPv4 bans didn't work back then, and they wouldn't work nowadays too.
I'm pretty sure that they're not gonna introduce a new system. GSLT works pretty well. Everytime an account's GLST gets banned, they earn another $15 for a new account with CS:GO.
This is nothing else than a money-generate system for Valve. And therefore they're not gonna change anything at the moment. And Valve loves delayed bans, we all should know that.
