Mmmm no. Two other main characters, as in names in the opening credits, died, and still have major parts on the show. Several minor characters died and came back. The showrunners said in interviews they were specifically unhappy with the perception that death didn't stick, and they wanted to change that with this death. So they were really violating their own setup. Everyone EXPECTED Quentin to die. We just thought that it was highly probably he would still be on the show. The permanence combined with the very, very weird send-off is what's upsetting people. And it's not as grimdark as "Magic comes from pain." It's often a very whacky, zany show, with darker parts, but it's not magical Game of Thrones.