Yeah, the thing is, all those guys are useless for varying reasons.I have seen the French do reasonably well if they have the support of the Spanish and Italian as well as the the Brits. But as you say, this is quite rare...
1)The Italians are almost never unified because the Germans almost always intervene and ruin everything.
2) The Spanish, if they even win the Civil War, are usually so weak for a while their support is minimal.
3) The Brits do fuck all to actually help invade Denmark unless you're directing their every move.
Plus whenever I play the Commune, I can never get past Flanders-Wallonia before my manpower goes to hell, and the Germans make some huge doomstack and break through Dijon. This is probably because I absolutely suck at the game though.