His first point, on efficiency, really should end the argument (and the others are, in part, derived from the efficiencies in the code):
Microsoft has taken a page from Apple’s playbook and designed an operating system that is extremely fluid and efficient. More cores would not really serve any great purpose with an operating system that is designed from the ground up to do more with less. The key is to understand the architecture involved here...
Unless an app is specifically designed to break up it’s processing mojo into equal parts, it will not allow the architecture to capitalize on that particular benefit. Most apps are not designed to do this, for a number of different reasons. Most commonly, these reasons range from the “It vastly complicates the code needed to do XYZ task” to “It’s a major pain to troubleshoot should issues arise”. At the end of the day, the benefit doesn’t outweigh the cost that goes into designing an app to make the most out of four or even two cores in a processor.
The lower capabilities required mean it's possible to create stunning handsets at a similar price point to the competition, or to push capabilities further down the portfolio - Nokia's Lumia 620 is a perfect example of this efficiency.
In the past, Nokia have trimmed the specs down on a device family and cut too close to the bone. The Symbian OS powered Nokia N97 cut a little too far in terms of memory and processor speed, and no amount of firmware updates could lift the performance to an acceptable level for many users.
So the manufacturers need to be careful. Lower specs do bring the bill of materials down, but that does not translate well to press and marketing. General consumers, and they make up the lions share of smartphone purchases, will tend to 'the bigger number is better'. There's a balance point in there, and I wonder how the Windows Phone manufacturers will deal with this during 2013.
Doud's full piece can be read over on PocketNow.