Charisma is not as powerful as prior but honestly stacking multiple charisma build heroes in the same city is uber for mid to late game. Power leveling a city to level 5 once your housing is in order and then casting enchanted hammers, stacking administrator heroes, and building labor guild plus the construction site thing means you can get your capital to a 0.0 production time - any building in one turn, including the end game level 5 buildings. Top that off with no cap on the city tile limits and you can create one hell of an amazing capital focused on gildar and/or tech. I had a game a few builds back where around turn 250 or so the capital had a pop of like 5K (level 5) and was cranking out like 1.3K gildar per turn and like 300 tech or something. Neat stuff.
I just landed on a philosophy where my sovereign uses his charisma to hire badasses to do all the grunt work. He travels around putting out mild monster spawns, levels in the process, and improves his ability to persuade people and champions to join his cause. If I can find her I have the sovereign marry Nabaja who is just plain awesome (dominate plus assassinate). Anyway, works for me but I fully realize other builds work too.