You're kidding right? That's like saying a Ferrari 599 is not that much different than a Toyota Celica because they both have 4 wheels and a windshield... The Ferrari is just "slightly" faster and has a few more features that "don't matter".
The 5:
Is more than twice as fast
Has LTE
Has faster Wi-Fi (5Ghz N)
Has a bigger, better calibrated screen
Has better cameras (sapphire lens and HD FaceTime)
Is Thinner
Is Lighter
Uses charging technology that will be SUPPORTED going forward
Has much more resale value/potential as the 4S continues to age
Has better battery life
Charges faster
I could go on... But the only people who really believe the 4S is comparable are the people who either are stuck without an upgrade (or can't afford it) or are Android folks fishing for flames. VERY few people (maybe 5 out of 100, IF that) would choose a 4S and $100 over a 5.
The 4S was a FINE phone (as the Celica is a FINE automobile). But there is NO comparison to the 5. It is simply a different (better, faster, smarter) animal.
You can say the upgrades "don't matter", but that doesn't mean it's true. They obviously do, or no one would buy the 5 over the cheaper 4S.
The 5 kicks some serious 4S tail... (and that's no shot at the 4S, which I still think is the second best phone on the market... it's just a teastament to the 5).