Excuse me, I must now rant.
I will never understand why people say that about season three, they were answering questions.
Funny that you say you dislike "useless characterization", yet then say your reason for quitting is because they killed off a character. Characterization is almost never useless; LOST, and stories in general, wouldn't be half as interesting without good characterization.
And I don't understand why Charlie's death would make you stop watching, when:
1. His death was predicted in the beginning of the season; there was no way around that.
2. His death actually got something accomplished.
Did you stop following BIONICLE when Matoro died? It's the same thing.
"some of them were like, whoops, we're firing the actress, so lets just kill the character off too" - What did you want them to do? Keep the character alive with a different actor, and some ridiculous excuse for why they look different? That is what kills shows.