Temecula currently has 35 established wineries, and there are 15 new wineries under development.
The Riverside planning department tries to find a delicate balance between interests, by designating areas for wineries, residential, and equestrian (horse ranch) use. While most approve of plans that increase prominence of Temecula as a wine region, there is growing concern about the impact of more visitors coming to the area (not in my backyard). Example of conflicting interests: traffic and noise from open air events at wineries, are concerns voiced by neighboring residents. However, weddings and concerts are a required source of additional income for most wineries.
Regulations applicable to the Citrus/Vineyard zone, like minimal acreage for establishing a winery or hotel, will also apply to the newly planned Winery/Hospitality district. Small size "garage wineries" (less than 10 acres) are not allowed under the new plans, but imo could positively contribute to the diversity and intimate atmosphere that stands for Temecula as a wine region.
With so many different interests at stake, there will be more public discussion needed. Expectation is that it will take at least a year before the new plans will be in effect.
Link for more information: wine country community plan