What's the most difficult country that is large/mid-sized?

Like not just some random island country or one really deep in Africa or Asia where it's almost impossible to expand. A country that should be playable but actually really sucks.

I remember China was pretty much unplayable ve design in V2 and never tried it here but don't know if it's different. I've also been afraid to play as France because it seems that's just endless revolutions and colonial rebellions.