"Is there any kind of legitimate planning that goes on in the development of this city?"
Yes, Kunming has city planning. If it didn't, then it would be a far more chaotic place than it is (compared to most developing world cities Kunming really is fairly orderly and planned out).
However, I sense that the operative word in your question is "legitimate". Seeing as this is a highly subjective concept, it seems you're looking for fellow commiserators to corroborate what you feel is poor city planning.
I have friends in Kunming's City Planning and Transportation Planning departments. They are smart people with good ideas, and they have worked in conjunction with city planners from Switzerland for years. The problem, they tell me, is that in the end, they merely occupy an advisory role. Party officials all too often ignore their good advice and make decisions that are contrary to good planning. When this happens, the good folks at the planning department have no choice but to wring their hands and shake their heads.
"It seems like it is just "let's tear up the whole thing at once". Has anyone lived in other cities in China or elsewhere and seen anything like this before?"
Um, yeah, like pretty much every city in China!
One of the main things city planners do is make zoning rules. Kunming does have these. You can't build a factory in the middle of the city. Kunming has something that most American cities lack: mixed use residential and commercial land use (i.e. stores on the first floor and apartments on the upper floors of most buildings). This is very much the result of planning (which also touches on the rules of the permitting process for business) and it is an example of good city planning. Mixed use development means that people can shop for groceries and daily goods without having to drive to a shopping center. It reduces traffic and is more environmentally friendly.
Another good example of city planning in Kunming is the subway system. While we have obviously yet to see its benefits, and have only suffered the inconvenience caused by its construction so far, it will definitely make Kunming a better and more livable place once it is open. Also, in conjunction with the subway system, the city planning department is carrying out transit-oriented development policies, concentrating high density development along transit corridors.
I don't mean to sound like a booster for Kunming CIty Planning. There's a lot of nonsense, too.
The wide boulevards and huge blocks facilitate added car traffic at the expense of the more pedestrian friendly fabric of older neighborhoods. Kunming is too preoccupied with trying to make life easier for cars, when it should be doing the exact opposite. Building more roads never solves traffic problems; it only creates more traffic (it's like what Kevin Costner said in "Field of Dreams"..."If you built it they will come"). The only way to curtail traffic is to actively disincentive car use by making driving a car expensive, cumbersome, and inconvenient. Ways of doing this include new fees and taxes on gas, vehicle registration, and car purchases, narrowing streets and reducing the number of car lanes, more strictly enforcing traffic laws and punishing violators, limiting parking, and traffic calming measures such as speed bumps.
I would add another problem in Kunming's urban planning is that all of the new development is aimed at upmarket clientele. There is not enough affordable housing for the working class, for new urban migrants. This is where city planning overlaps with larger socioeconomic policy and is not the under the purview of the city planning department. Any changes in this regard will have to come from the city government itself.