What is the plan for Bans, which get nerfed every time a new champion is released?

So there are approximately 140 champions in League and we have 5 bans on our team.

Seven champions have been released since the 5 bans/team structure was implemented, meaning ban effectiveness has been weakened by about 0.5%. It's only going to get worse until this critical issue is fixed. I will not stand for this.