Agreed this was super OKC focused (almost felt like OKC planted story if it wasn't the NY Times!) but the data supports the fact this is a broader trend.
Could be OKC is just good at PR. The mayor is an ex-TV celebrity and a perfectly reasonable person who makes a good interview. They interviewed him on NPR recently and his side was, in summary, they needed to spend money so they raised a tax and spent the money.
http://www.npr.org/2012/01/19/145437581/oklahoma-city-avoids...
It's a pretty good example of why Republicans make good mayors, even when state and national level Republican politicians are insane.