Well there again you'll find an interesting dynamic though. Blitzes will rely more on early game strength. Smaller maps with less than 15 provinces per player and less than 10 players will shift more towards mid game strength being of primary importance in victory. While finally, larger and longer games is where the late game strength will more often be the deciding factor. (though any game that is mid-late game focused will still be affected by the earlier stages of course, just that late game strength is meaningless in a blitz game)
So theoretically, if there were an enormous amount of ratings submitted, MP Ease of Play would be skewed slightly towards early game strength, where a nation whose strength progression went 5-3-3 would tend be consider better for MP success than a nation who played as 3-3-5. But mainly because we're not differentiating between lengths of games, I thought rating in 5 different categories was a good compromise between detail of the data, and user friendliness of the chart.
