Before continuing, I want to make this clear: This isn't a rant by a fan/"fan"/purist of the franchise. This isn't a statement made by someone who is upset about the change of Sam Fisher's voice actor and his illogical role as a younger version of himself in the future. This isn't a biased complaint about the addition of more combat elements which may overthrow the stealth gameplay. This is simply a speculation of how Splinter Cell: Blacklist's stealth mechanics may possibly be something to worry about for Sam Fisher's latest outing. But bear with me, as this is all simply a matter of opinion and isn't a self-proclaimed cold, hard fact about the game itself.
Set to release in August, Splinter Cell: Blacklist sees the return of the famous three-eye goggles. Oh, and Sam Fisher, too. Advertised this time around is apparently a larger focus on stealth gameplay, which any fan of the series can definitely get behind on, although that's not to say that the combat mechanics from Conviction are abandoned. They're actually still here, bigger and better than ever, although according to some previews and Ubisoft, it isn't there to overshadow the stealth element, so to speak. Ubisoft promises the ability to use any of three tactics to wage war on your enemies, two of which utilize stealth (one of those which are quite up close and violent), and one that's all out crazy, for those with little patience.
But if Conviction is anything to go by (and this game is a lot like Conviction, apparently), this may not be the best course of action for this franchise, if only because the franchise wasn't built around anything other than stealth. Now, departing from that being your only option, the real problem arises: there's no incentive to stay stealthy.
Even without the human shield, those guys with the goggles don't stand a chance.
In earlier games in the series, up to and including Double Agent, when playing as Fisher, you were never well equipped for combat. Stealth was pretty much a necessity, and although you can actually gun your way out of most situations, many of the encounters in which you find yourself caught were really, really tough. Essentially, if Fisher was caught, you were screwed. Most likely, anyway.
Come Conviction, it was a game changer. You can still stealth through most of the game if that fitted your fancy, but the issue was that there was no reason why you should stay in the shadows. Sam Fisher is way stronger. Way better equipped. He still goes down in only two hits, but the weapons he has at his disposal make him a killing machine that would make the player character in any Call of Duty iteration jealous. This wasn't because of the Mark and Execute feature, surprisingly. Sam was an all around better fighter, in every possible way, to moving faster and more fluidly (which is actually a good thing), to having a assortment of upgradeable weaponry.
So how is better maneuverability and better equipment a problem? The problem is that stealthing became too easy. It was risk free. If Sam Fisher was caught, the entire room was almost guaranteed to be covered in blood, but not blood from the series' protagonist himself. Following the bloodshed, the enemies became unaware of your presence in the next room, or otherwise are aware, and don't do anything but call out your name in anger. You lose nothing from getting caught, except the self-satisfaction of being able to ghost the level. At least in the old games you weren't equipped to fight back. In Conviction, there was always the ability to go into combat mode, against enemy AI who were built from the ground up to get tackled in the shadows.
There's no guaranteeing the enemy AI won't be better for combat than in Conviction. In fact, with a larger focus on the combat than ever, it's a safe bet that they're probably more competent at gunning you down than ever before. But Sam is actually thrice as powerful than in Conviction, with a whole host of new and impressive gadgets. The likelihood of the AI being more of a threat to you in Blacklist than its predecessor is low.
Especially considering some of Sam's stealth aspects being greatly improved on, for better or for worse. Take the drone in the demo, which can silently and non-lethally take out enemies from a distance. That thing is hard to spot, and takes down enemies in a single bullet. It renders some actual sneaking rather unnecessary in most cases, especially since taking down enemies in the "Ghost" mode with the drone can potentially clear a room, so it doesn't produce problems like in older games where enemies can spot knocked out buddies and go on alert. Perhaps a better course of action would be to at least make it tag enemies, rather than shoot them down.