I have (had, until I killed it) a Galileo. It is(was) a great board -- well beyond most other IoT offerings. It runs Yocto Linux, which -- is just fine for that, except that Linux is a bit of a bear -- it has little in the way of vendor supplied HAL and bringing it up can be frustrating.
I doubt that plopping even WindowsCE on there is going to improve that situation much. I am very satisfied with SecretLabs work on the Netduino, however -- there are still areas that elude me -- I2C, for example.
You are simply suffering from life on the bleeding edge and why would Microsoft invest vast resources to develop this when they use their users as beta testers and have done so for over 20 years, now? So, they are a bit bogged down, that is the same everywhere in this industry. I have issues with every single development system I use -- most of them turn out to be me in the end.
JoopC -- pardon my observation, but -- that is a very naïve opinion about C++ -- it is still one of the most powerful languages available. In fact, most more modern languages are actually written in C/C++. Even Unix could not be written without C. What are your specific objections to a language that gives the power (as well as the responsibility!) to the programmer?