Pretty normal reactions. People who don't search for every bit of info of the game. I can read these comments in the german forum too, although they are more in detail and in a more polite manner. It's really not surprising. One side wants the Splinter Cell experience the other ones want them to get a long with the evolution of gaming.
It's often that these people talk at cross puposes. The problem isn't the fast pace or the slow pace for example (while developers often do use these words to justify change of direction). You can have the fluid gameplay, which I assume that's where CT2 may have gone anyway (Just how I view the development through the legacy series, you don't have to agree with

), and the classic gameplay. You see that a lot of people want variable speed back and that's where the link between classic and aggro is. Both styles have to care for the core mechanics. Like a Ghost, so does a Panther need to be aware of the enemies too. A lot of features were linked to the variable speed which added a feeling of having an indepth dynamic stealth system. The difference is that the Ghost only kills/KOs when necessary and avoid enemy contact as much as possible, a panther has a wider range of playstyle opportunities. People who like to KO all or to Kill all undetected and are not too strict to themself when it comes to enemy contact as opposed to a Ghost are also Panthers. They may use Sonar Goggles and KIM for the higher density of AI but they don't have to. They play a lot more with the AI, cats & mouse games. CT wasn't that far away of that direction in my opinion. It needed Level Design and AI placement that suits both the Ghost and Panther player (for the Action player you don't need it extra) and variable speed on pipes and ledges, additionally the Cover system and that's it.
Now where I wanted to go is. They need to advertise the variable speed and Closer-Then-Ever again and you got them. Both the Ghost and Panther are players who get close to the enemies. While the Panther may now use features like KIM and SG (Sonar Goggles) the Panther also should be able to do all the things which you could do previously just in a more dynamic way (variable speed). I think it's a misconception that only Hardcore Gamers, Veterans and Ghost players have these concerns. More often these players fits more to a typical Panther (Predator) kind of player as you could imagine. I do myself enjoy very much that playstyle of a predator and panther (while I do not use M&E in Conviction).