People try to tell us BB is not the final villain when he's done nothing but clown the Marines and the WG. Now this. It's insane.
Hes the Shigaraki/AFO and Zeref for Luffy, hes surely gotta be the final villain. Thematically, hes the most fitting villain and the most ambitious, the most bold and has manipulated fate to his will, risked his life and thus taken massive risks just like Luffy and made massive gains for it.
Even if he doesnt have CoC for some insane reason, hes truly a D after all and absolute menace, the most iconic, charming, recognisable and thematically fitting villain for OP. I love villains like Doflamingo, Kaido, Crocodile etc but Blackbeard is the perfect foil and villain to Luffy.