Coming from a launch day 2009 3GS which, although it still works as it should, is showing signs of its age and isn't exactly "fast" by today's standards, YES.
That said, given that I skipped the 4 (had early upgrade option when it launched, but I passed) because of things I didn't like about it, I surely HOPE they at least do some things differently. I was not a fan of the glass/metal build or of the antenna issue. I also concur that the screen needs to be bigger than 3.5".
So yes, eagerly awaiting the iPhone 5.