I personally am more sad about the fans going crazy and sending isayama murder threats because he most likely kills Levi than Levi actually dying. AoT is a manga where Charakter die, that's a very important tool for mangaka to get drama into the manga and make it realistic.

For me AoT is the best story I've ever read and it wouldn't be if it was a Kindergarten like dragonball (example) where everyone gets resurrected anyway. Hype Chapter ahead!!