@Muufle every decent programmer closed their client by fear of Activision/because of direct/indirect C&D repercusions. The only T7 "clients" left are copy pasted crap run by clueless people. They're not clients, they're archived clients brought back to life by people owning a VPS pretty much.
BO3 is and was always an issue, you can easily see it and understand why + the game has pretty much everything when it comes to modding already so the interest is very limited for Plutonium developers.
What you're asking for is essentially
"Please put 6+ years worth of work (Plutonium) at risk to fix BO3 security issues (that already have solutions) to add nothing else to the game other than security, and although every other clients got taken down"
I understand your concern but you need to understand that Plutonium is not gonna risk losing everything "just" to fix a game that already has several things fixing it to an extent and when we saw other clients get killed right in front of our eyes