The factions are simply not appealing from design level even if potent. And lets not forget that they had a plethora of their own balance problems as well where units scale badly or don't scale at all and you are forced to relay on doctrines way too heavily, especially for late game, which limits already limited options even more.
Pretty much. The primary reason I play allies is because the searching number is almost always >80% searching as axis when I start the game, not because I particularly want to play as them. They have lame, limited and boring gameplay compared to either axis faction. If I want to win as soviets I'd better sure as hell have one of the five competitive commanders selected (Shock rifle, Guard Motor, Guard Mechanized, Shock Motor, KV1), and if playing against OKW I have to start with sniper or maxim spam and move into spamming shocks or guards because cons and penals are worse than useless, being outclassed straight away by freaking volks and getting worse from there as the game continues.
Playing as USF I can already tell if I won or lost the game at the 10 minute mark. I might as well quit at this point if my opponent has held to a reasonable amount of territory and/or hasn't really taken any manpower losses. Build variety is limited to: 3 rifles + 1 assault engineer or 4 rifles to lt or captain to m20 or stuart to Major and sherman/m8 spam or skip major and Armor company bulldozer spam. On an open map I may be able to build one howitzer before the tank spam phase, wooh!