The Marines taking Ls after Ls is not completely bad. It just means when they come back, they will come roaring.
Honestly, I am sick of Pirate vs. pirate stuff in the manga. If Oda finishes this in 3 years with BB being the final villain, then the OPverse will lose a lot of lustre for me.
You have this massive world, so many fractions (Marines, WG, Shichibukai, Revolutionaries, Yonkous), and then boiling it all down to Luffy vs. Blackbeard is straight up garbage.