See, it completely and utterly baffles me how anyone could say a phone wouldn't make sense to replace a desktop, I mean really baffles. Have you read about windows continuum feature in windows 10? When docked your smartphone will act as a regular desktop PC, just dock it into a mouse/keyboard/monitor. That's a FULL windows computer, not a watered down version of windows. Atom CPU's have already demonstrated just how powerful they are, there should be no issue running PhotoShop, MS office, etc etc. There is more than enough power there to drive desktop type programs easily and then some. This is even more amazing in countries in which the only computer some people have IS their smartphone.
And to specifically address your question what non-Apple phone could do a better job? Well, all of them. Heck even Android has mouse capability and Google gave it some desktop power. iOS simply blows itself up to fill up the monitor, but the OS does not change at all, you still get that grid of icons from 1998, it's easily the poorest solution to replace a desktop, by far. But that's by design, Apple stands to lose a lot of money if you only buy one device, but this way you are buying a desktop, laptop, tablet and phone from them, smart company.