I think that's two very different things - a complete set of features done poorly vs. an incomplete set of features done well. In general it's best to err on the side of the latter, it's going to give the customer a better UX.

What exactly was the original iPhone missing? The only thing in the OS I recall was copy/paste. The other things we'd take for granted today likely weren't conceived then, including the App Store. The main issues was that it was a frustratingly slow experience, so OS/proc performance, and EDGE which was the best widely available at the time was insufficient.