Update: Reply from Ubisoft (not to me directly of course, but to this general sentiment)
According to Beland, the team at Ubisoft Montreal spent a lot of time looking at previous games in the series to decide what its core values are. Beland said that the series does a good job of providing the "fantasy" of Sam Fisher, but that the difficulty was turning off some players. "What was coming up all the time was, 'Man, that game's hard. I played the first map and I stopped. It was too difficult,'" said Beland. He admitted that sales of the Splinter Cell series declined from the first game to the fourth.
Thus, the team decided to focus on the values of Splinter Cell -- stealth, light vs. shadow, etc -- and look at them in a different way. "If you're the best elite agent in the world, if you're Sam Fisher," asked Beland, "why do you have to hang off a ledge and move at one centimeter per minute?" He added that the team wanted Sam Fisher "to be a predator, not a grandmother." This concept led to concepts like the Mark and Execute feature, giving players the feeling that they really are an elite agent.
According to Beland, such changes to Splinter Cell are part of the delicate balancing act in which the game industry is currently engaged. "We need to stop making games that are super hardcore," said Beland, "But we're afraid because we don't want to lose the hardcore people!" He added that "it's a real challenge" to make a game that is both accessible to the casual audience but still appealing to the hardcore.
We have to make the bad players feel like a badass, or else they won't buy our game!
I like that he at least acknowledged that making the game too freaking dumb and simple will turn off the "hardcore" audience who actually play games to play games. Of course his opinion on it is "screw the hardcore" which is disappointing. One hopes it will tank and teach them a lesson, but it will probably sell like gangbusters.
As gaming gets more and more a mainstream industry this is just getting more and more sad.