I suggest a quick look at Stephen Shore, Joel Sternfeld, Joel Meyerowitz and Alec Soth to get an idea about the sort of street photography work that can be achieved with a 10/8 camera and whilst your at it check out dusseldorf school of photography and the exibition new topographics.
On the point of sharpness one of the most famous American photographs ever taken is soft, and it matters not a jot.

ttp://www.loc.gov/pictures/collection/fsa/item/fsa1998021539/PP/