The feeling about what enemy could face Luffy after he beat Rob Lucci, it is the same as we feel with Kaido. After that fight I could not imagine what kind of monster could ficht Luffy face to face, but guess what?, Oda changed my mind. I'm not worried at all for that, Oda always finds a way to make the next enemy threatening, maybe between enemies before final enemies (BB and Admirals, I don't think Im will be a strong enemy) are going to feel weaker (like Hodi, Ceasar, etc), but that won't stop the story to be fun like always.
For my part, I'm happy with this arc, I like how Kaido was defeated, the double page shows a lot, how luffy with his wishes overcomes Kaido wishes and win because his emperor haki (related with will) overpower Kaido. We can see how strong the punch is when Kaido dash super quick and the explosion in the earth, finally seeing the wishes of wano people that wants Kaido to disappear, for me it was an amazing double spread with a lot of meaning. It is truth the double spread of the final attack with Rob Lucci looks amazing, but it is only one scene and for me this double spread has more into it.
And I'm not so angry about Luffy reawakenings. The first one served to make Yamato shine, the second one served to make Luffy fruit awakening and the third showed us that luffy is totally tired even if he is using the awakening state of his fruit (we will see in the aftermatch the consequences of using the fruit in such terrible state).