Of course it will - it's not exactly old - use some rationale - if the 3GS can run iOS 6.1.X, and it is 4 years old, then why on earth would a 2 (or less?) year old iPhone not run iOS 7?I hope the 4s runs 7. That would be greatly disappointing.
Sure it might be powerful enough for it, but considering the past years and how the limited the "bigger" functions to the newest handset(s), why would they suddenly make everything available on the 4S?I'm pretty sure it will not only be on the 4S, but it won't lack any features. The 4S is still powerful enough that it will be able to run any feature of iOS7.
I seriously don't think it would happen. I think the new design is going to be for all the iPhones and iPod Touches. Although, the 4S will lack some features. Good thing I can get an upgrade when the 5S or the 6 comes out!iOS 7 will be released with several new features, one of them is a fresh new designed UI exclusively available for the iPhone 5 and the upcoming iPhone 5S only.
I hope they don't do something like that lol.