ORIGINAL: canuck64
Kornish-we're very much agreed on the AI-which is why I went to the horribly geeky choice of playing myself hotseat for all factions.
Years ago, my best friend and I had a 2 player game of Diplomacy going, until college-then we got 5 others in on it-and things got really complex...we were drafting propositions in officialspeak of the time and so forth. Back stabbing occurred, but the stabbee would inevitably let it be known this had happened.
COG would make for a great 3 or more player game. France, Austria and Britain can be the three leads, the others you can (as you suggested) work on thru the in-game diplomacy.
3 differing motives here would augment the diplomatic model.
FInally, arguably-you're playing the one power I'd have to agree on that really doesn't need to work on diplomacy too much. It seems England is the go-to guy of the minors when they're concerned about motives of their (adjacent)land-locked brethren. Ironically, unless it's a coastal entity-having Britain as a protectorate is often like kissing your sister, unless the minor in question actually has an army per se.
Britain's the spoiler, no doubt. But are you on the continent IN FORCE? That's the hard part.
Everything but my militia was on the continent, and now heading to Corsica.