I like a happy medium myself. For whatever it is worth, I've found that despite an appliance-like nature, I can extend iOS with third-party and custom software to my satisfaction. The key point here is that I don't have to resort to such in order to have a good experience as an end-user.

I'd argue that iOS falls between the extremes you've highlighted. It isn't really a general purpose computing platform as evident in the differences between say how multitasking and filesystems are implemented and what they expose to the end-user. On the other hand, the core OS has always supported preemptive multitasking and has always had a real filesystem to boot. The limitations of the presentation are inconveniences to be sure, but still I can slap together an app in Objective-C or Swift and slap it on the phone with ease.

That said I'm sure there are some tasks more easily achieved on traditional systems. That noted, if memory serves this was also the case with the PC/desktop transition. Desktops couldn't do everything big iron could do, but they did enough, it would seem.