I'm not riding any nostalgia cock. Stealth games are already niche. When it comes to stealth games, you have a selective amount to choose from and most of those have turned into crappy hybrid games. When it comes to stealth I prefer pure stealth games.
In MGS3, if you go on a rampage, there is a high chance of not surviving. Enemies don't play in that game, and cqcing multiple people isn't exactly easy. Your argument that MGS lacks choices in areas is also false, especially if we're talking MGS3. MGS3 has numerous pathways and ways to handle each area. DXHR relies on vents and hacking doors. MGS3 relies on using the fora and fauna of the environment (grass, climbing trees, hiding in stumps, pretending to be an alligator in swamp lands). The point is, the games allow for numerous ways to tackle any one area via espionage. DXHR however plays the exact way it does from the outset.
Skip upgrading?
When you use that argument, you're already out of it. Not kill enemies IS a good challenge in DXHR, though. But upping the difficulty (trust me I tried) doesn't really change the AI behavior patterns.
VIDEO Like I said, DXHR is an okay stealth game. But to put it at the top of the stealth genre this gen proves my point. Stealth has gone the way of survival horror. If you don't like horror or stealth, cool. But I love both and haven't played a new great game in either of those genres in years.