Ninja'd Fort Hill without breakin' into open combat on any occasion. Kill 15~ soldiers incognito? Check. Backstab the captain without bein' detected? Check. Blow up the powder reserves 'n swap out that dirty Brit-flag for the 13 stars? Check. My stealth skills in AC:III have clearly improved exponentially for... uh, no real reason I don't think. Ain't like I play stealth modes in Multiplayer these days anywho. Social stealth gets borin' after awhile.
... 'Cept in Single player, since it's actually hard at times.