To a developer his tools are just as important to his work as in any other profession. When you are a carpenter then you need the best hammer that you can afford. No, you might need the most expensive hammer to be able to do your work, but the better the hammer the more efficient you are. The same thing goes with a plumber as well. If you want to be a plumber that is efficient then you need to have the best tools around you. No, tools do not make the professional but they sure do help a lot.
This is the same for a programmer as well. When they start to use a new system, even though it is an upgrade of an older system that they may have used before, they need to make sure that they are going to be effective on it. They need to know if there are any special parts of the new operating system that are going to affect the way that they work. So with the new Windows 8 being released, developers are making sure that Microsoft has everything right before they jump on board.
A new paradigm, for creating
The first feature that a professional programmer is going to notice is that there is a whole new programming model on Windows 8 now. When you are on the Metro side of the operating system you cannot use all of the functions like you once did in your favorite programming language. They have made it so that you are very limited in what you can do. You still can use most of the features in your expressive language but some of the more dangerous ones have been cut out completely.
The reason why this has happened is because when you are using the Metro portion of the operating system on a tablet, Microsoft wants it to be a delightful experience. They do not want to take the chance that any third party application is going to make the entire operating system difficult to use. This means that in internet explorer they are going to eliminate some of the abilities that it has gained over the past couple of years. One of these abilities is the ability to have third party plugins. Sure, you will still be able to use Flash and other plugins but just not in Metro mode. You would have to turn your tablet or desktop back to desktop mode to be able to use them.
So as you can see there are going to be a lot of changes for developers when Windows 8 comes out. Now it is up to the developers whether they accept them or not.