Capacitive screens were already used by one terminal, I think an LG phone. But the iPhone put something different in the market: multitouch and gestures. Some things like slide to unlock or pinch to zoom seem trivial now but they weren't really product of the normal evolution of phone interfaces. Locking the screen was done with a hardware button because it was deemed safer, zoom was double tapping in the part of the image you wanted to magnify.

Had the iPhone not been introduced I doubt small little details like these would have changed at all, and there are tons of these small subtleties in the current smartphone OSs.