I'd love a game set in Edo-jidai, but in Osaka (where I lived for many years). Osaka in those days was a major trading hub, with a grid pattern of canals throughout the city to facilitate freight movement. Think of a Japanese version of Venice, basically. Gondola-type boats, barges, palanquins through the streets; maiko and geisha from Kyoto on their way to entertain some powerful or wealthy client. Osaka also had a large community from outside the prefecture(in Edo-jidai, travel was still very restricted for all but the wealthiest/most powerful). If you were a humble farmer forced off your land, or a ronin who had been wronged by another samurai, etc.; if you escaped your home prefecture you'd end up in Osaka because there was always work in Osaka. Be it tending the rice patties in the East and North, labouring in the docks, or the more, shall we say, questionable work.
Basically, a 'free world' but limited to Osaka prefecture. WITH SEASONS. The Japanese will tell you untill they're blue in the face that Japan is the only place in the world that has distinct seasons - now whether that's true or not I'll leave to you to laugh about, but the fact is they are very clearly defined. You'll step outside one a November morning one day and the wind has changed - there's a dry chill in the air - Siberian wind heralding winter. In March-April you'll get ume (plum) blossoms follwed by the sakura (cherry), and as the groudn is still thick with petals in May you'll get tsuyu - a monsoonal season that heralds an impending cicada-thick humid summer.
Maybe some kind of 'story' quest that follows a battle for supremacy of the city between a local daimyo, some yakuza-types, some farmers wanting a better lot in life (a la Way of the Samurai II). You could even slip in some secretive Christian cults (Christians didn't completely disappear in Japan during Edo - many formed secretive cults that kept their religion hidden and, over the centuries of isolation, became ... something else). Get work as a bodyguard for a wealthy merchant (a la Yojimbo); gather other ronin to help an outlying village coming under bandit attack (a la Seven Samurai); hunt down and duel the man who killed your father (a la Kengo III); join a ninja clan and take missions (a la Azumi or Tenchu).
Hearthfire style you could buy property; GTA San Andreas style you could have gang conflict for control of suburbs; Fable style get married and have kids, Yakuza style partake of cultural festivals with minigames and little rewards, and Tenchu style run across the rooftops and garrotte guards.
DEEP FRIED AWESOMENESS ON A STICK WITH BELLS AND WHISTLES !!
Now shut up and take my money !!!
