I don't understand why people want their faves to be the final villain so bad, who tf cares if you are the Kaguya of the One Piece verse. Madara is the one who left the mark. Being impactful in the final saga, and/or being the penultimate villain is arguably more interesting.
Final villains usually have lame buffs that ruin the character anyway. I did not enjoy Hogyoku Aizen more than base Aizen, no one did.