The plan is to build residential apartments in the southern section, build an access road from 29 to Preddy Creek Rd, then have a large retail center (I had heard rumors they originally had WalMart planned to be the retail center but plans fell through because the owner would not sell the land to WalMart) in the central portion, and then the northern portion toward Sheetz would be a mix of commercial retail and office spaces. To see a pdf of the plan, see the attached blog entry.
As for impact to the neighborhood off of Mathew Mills.. which one? While this development will obviously increase traffic to the Matthew Mill/ Sheetz intersection, the land improvement will also improve land value for owners in the area based on similar developments in other parts of Charlottesville and Greene County. However, that is also based on getting tenants for the property.
It's good to note that this property has been planned for many years and as of right now, there is no actual start date for any type of construction. I believe the owners are still waiting for Greene County to provide public sewer services to the area.