Yeah, I never watched Talking Dead but I knew that if you happened to see an actor sitting on the couch, it was usually a bad sign.
And it sucks that they would kill of characters just for shock value (I'm guessing Abraham fell into that category...tried to use him as a 'fake out' making people thing that Glen wasn't going to meet the same fate as the comic book, but it didn't work out that way). The nurse/doctor that took the arrow (to the head I think?) the one that was Tara's g/f I'm thinking was another. Same with Beth when she bit it by getting shot after that whole mission to rescue her. And those are just right off the top of my head.
Maybe that's why Maggie et al have pre-emptively left the show and sought other work, so they don't get some "shock ending" that they don't deserve. And yeah, I remember the dust up about how they treated Chandler and his character being written off. It was BS, like you said, he's one of the originals, he deserved better treatment as an actor than what he got.
As far as Andrew Lincoln, maybe part of that is true, but he did agree to do some movies though.