Yeah, it's always sadder when a character is taken out not by death, like in the case of Audrey. If she was just "dead in China" that would have been lame, but having her physically there but unobtainable for Jack was heartbreaking. If Curtis was the one who got his eyes blown out instead of Doyle, it would have been horrible because we knew him so well. With Doyle, even though I kind of liked the character, when he got blinded it was just like "Welp, looks like he's going to be another one of the single season characters. Oh well..."
The only benefit to Curtis's death was the short term emotional impact it had. You were still shocked that they took out such a likable guy and before you could even recover, the nuke goes off and that's another punch in the gut, shock wise.
The other weird thing about Curtis was his character arc. When we meet him we question his professionalism with the stuff with Marianne, but then we see that even though he's human, he approaches it in a very level and professional way, and stays professional for the rest of season 4 and season 5. Then in season 6 he just throws all that away and takes a suspect hostage out of nowhere. It was just a bummer.
I wish season 6 never happened. So much nonsense. No serious repercussions for Jack in China either.
Am I talking spoilers too much? I feel bad for anyone who's coming in here hearing about the new season and reading spoiler city, but it HAS been a long time since this stuff aired.
To be honest, I think part of the mistake was birthed by the end of Series 5. The China cliffhanger was something that probably sounded cool during Series 5, but then when they sat back to bring him back for Series 6, they were left head scratching.
Things in Series 6 that are a direct cause of the China cliffhanger:
- Wayne as President. They wanted somebody who would "truly feel" how hard a sacrifice Jack's life is in the opening episodes and then want to side with him later on, so they needed somebody that knew him. That was why it ended up Wayne.
- The nuke going off - they needed a game changing, brutal event to keep Jack 'in', because after his ordeal he wouldn't want to stay
- Audrey. 'nuff said there.
Those three things are the jumping-off point for three of the weakest parts of that Season - Wayne is ineffective in that role, despite being a good character. They appear to realize that halfway through and initiate the injury plotline for him to give him some stakes, but it falls flat. After the nuke the plot can't live up to that moment, and there's also a problem with the world as depicted showing no reaction to the nuke two hours after it happened, because it's an unsustainable concept in a real time show where things have to happen. Audrey - just a complete misstep for that character.
I think the ending of a Season is important, as it really builds a place for the show to go. If you look at Series 4, for instance, I don't think it's the strongest season - once Marwan becomes the primary target the season just feels like it begins to meander and lose its focus - but it has an incredibly strong ending. Series 5's utterly incredible delivery owes a lot to groundwork laid in Series 4 with characters like Bill, Edgar, the 'new' Jack-loyal Chloe, Audrey and so on. Of course, even if you remove the China thing, there's still the putrid Bauer family stuff in Series 6 and all that... so you can't win 'em all. That series would've likely been an entirely different animal without the China angle to shape its early hours, though.
They know where they went wrong, though. There's an interview somewhere recently with Howard Gordon where he's talking this new Series, and he says where they went wrong in 6 was that they didn't have a plan. 1, 2 and 3 all had arching plots overall constructed prior to the first episode being written. They might change, they might evolve, but they had an idea. Series 4 they did away with that, and despite it (imo) being weaker than the first 3, it was the most successful, because it was very action-packed and stuff. And it was still fucking great, to be fair to them. So after Series 4 they went with even less planning in Series 5, and that was just the perfect storm. They had no pre-plans - like when Walt Cummings is revealed as the 'mastermind' and kills himself early on, that was probably written (and acted) as genuine, but then writers later retconned it so that he was protecting Logan and was killed to prevent him from implicating him. Which is amazing. By Series 6, that bubble had burst. 7 was more planned out, 8 was a mix again - with 8 they had the first and last few hours planned out - until the first attempt on Hassan's life, and then the back-end after Renee's death were planned from the start - but the middle was free-form. I felt that worked well.