J.K. Stockholme
Right Opposition
EP/MP is a bad measure of wealth for several reasons. EP does not equal gross domestic product, and MP is only the available military population, not the actual population of the nation. Thus, a nation might have a glut of military aged males, due to not having most of them killed in a recent war, or they might have a government that acquires very little tax income from its population, for varying reasons. This hypothetical nation has high MP and low EP, which would make it look bad, while the actual wealth of the population could conceivably be much higher. Also, EP says nothing about wealth distribution, which is important when consider how 'poor' a nation is.
I don't think EP is revenue from taxes. Prosperity seems to be directly linked to higher EP, so I would actually say it is very much like GDP. Find a prosperous nation with poor EP in this game, that is to say, a country with nothing to spend, but immense economic influence, and you'll probably only have found the exception. Though I don't think they exist.
MP is though, not so great for anything. The reason I for one bothered at all to note the economic points in Europe in my map was because we have hit a particularly peaceful little moment. This would mean manpower and EP should be, shall we say, gravitating to their "natural" state. So the EP/MP measure could have the tiniest shred of value.
@Jehoshua: regarding Sardinia, I would argue its not even a strange instance; that country has been rather brutally economizing its tiny island state for as long as I've known. They're the model economy for extremely efficient use of land. So their high EP to MP is actually a good indicator of their prosperity, I think.