Noooo I liked the WN's ending! Yuki was the final boss since he thinks he's the reincarnation of the dragon king because of the memories and after Rimuru absorbs the other dragons just like he did to Veldora his hair becomes silver-rainbow colored, defeats Yuuki, go back to Earth moments before his past self dies, resurrects him and lives in the two worlds. Ramiris even shows her original form in the fight! I want to see that!(/TДT)/
I think he is the reincarnation of the dragon king ang rafaela is her wufe in the past life whuch is basically meams they are melims Parents. Hahahha.. JUST KIDDING!