Urban Planners have shown a number of benefits to a city that successfully mixes residential, retail and office space:
Vibrant, Diverse Cities - Those with mixed use offer the most social, economic and racial diversity. Think New York City or San Francisco.
Fewer Dead Zones - Who's never felt spooked walking in a deserted, downtown financial district late at night
Safer Neighborhoods - Nothing drives away criminals like active streets. People walking, open stores, neighbors sitting on the balcony. These are thieves' worst enemies
Healthier Residents - Getting people out of their cars and on to the sidewalks may reduce health care costs
Happier Residents - Studies have shown that shorter commutes lead to happier lives (Limited Infrastructure Costs - When people are densely mixed with businesses, roads, power lines, and sewer pipes are shorter.
Preservation of Green Space - Then Envision Central Texas vision has fewer, denser developments and more open land.
Studies have shown clear linkages between the traits above and mixed use developments. But a linkage doesn't necessarily mean causation. Are cities diverse and vibrant because they have mixed used buildings or is it just that mixed use development isn't successful in a city that isn't vibrant? Maybe people just want to live where the action is.
Does living in the city make you skinny, or do people who don't like walking everywhere just move to the suburbs?
Even if you accept that mixed use actually helps a city meet the goals listed above, I think it is important to remember that the goals of VMU do not include:
Neo-Quaint Architecture - Mainstreet at Disneyland doesn't qualify as vibrant street life.
Higher Tax base - The goal should be lower cost per capita, not a source of cash to subsidize low density sprawl in other areas of town.
Rows of Boutiques, art galleries and day spas - These maybe tourist draws, but they are not the makings of a vibrant city.
I don't have anything against neo-quaint boutiques or luxury lofts, but the government shouldn't be subsidizing them at the expense of affordable housing and neighborhood businesses. The city should not distort the market to encourage developers to tear down affordable homes and commercial space, only to replace them with luxury condos and chain coffee vendors.
VMU development is part of a New Urbanist trend that is sweeping the country these days. In general I support most of the priniciples of this movement. But I'm concerned when the city tries to force this trend on a neighborhood with regulation and subsidies.
For the most part, the mixed use projects in our neighborhood have been developed on "brownfield" lots. (Sixth & Brushy, Waterstreet lofts, Saltillo lofts). Duplexes going up in the neighborhood are unaffected by this ordinance. I'm not aware of any VMU style projects that have actually torn down existing housing/commercial space. But this is only a matter of time.
In short, there seem to be reasons that the city would want to see VMU development in any neighborhood, but there are clearly concerns about why the city wants to see VMU development in our neighborhood.