Shawn was walker bait from the get go. He had to die for the canon to remain canon. He was already dead by the time of the original story. However appropriate it might seem to be able to save him somehow that is one instance where, as a prequel, there was only one way it could go down. I'm cool with that.
However, I do hope Telltale focuses on real choices with consequences and sincere differences rather than the illusion of choice. Glen's being annoyed no matter what you do might be a problem, but then again I've met a guy like that. In a tough situation like that one there is no right answer and some people, perhaps not unlike Glen, wouldn't be happy with ANY choice you made. Naive to be p hoping there was some happy ending for the lady, but there wasn't, and Glen couldn't see that until later (as witnessed when he suggests he understand why you chose to let her off herself if you took that option). At least that's how I see it and it fits within the way they have portrayed Glen, to me.