Things change. User interfaces are refined and usability is improved...if you give them a chance. There's a small amount of time with less productivity until you get used to the new way of doing things, but after you've learned the new way your productivity will have increased.
Is UI configuration and function an absolute in terms of productivity? Or is it a preference? I happen to think it is very much a preference. Different people work best in different ways. XP and Vista both gave users a choice as to how they wanted to work with the Start Menu and Task Bar. Win7 removes some of that. Is that progress? Depends on your perspective I guess.
There is nothing wrong with you liking the changes and feeling that, if you give them a try and get used to them, you'll probably like them. But what if someone (like me) has tried them, for quite a while (several months now), and still doesn't like this new way of working? Are they wrong, or is MS wrong for removing options? Did they need to remove options to enable some other new function, or was it just them wanting to move everyone into a more consistent way of working, for support reasons or whatever? It's certainly their perogative to do this, I'm not arguing that, but I don't agree that it is unquestionably an improvement.
But maybe I just haven't figured out exactly how to use it. Here's a question for you, maybe someone has a solution: Assuming there are benefits to spatial memory and association (e.g. the Start menu is always lower-left and you can quickly move your mouse there to activate it at any time), how do you maintain that with the pinned apps on the task bar when the pinned apps move as e.g. several windows of an app to the left of it in the task bar are opened (if merging of app windows is disabled as I prefer). This is especially problematic if you enable labels for task bar entries, as I also prefer. One of the reasons for having them on is I can glance at my task bar and get a quick idea of e.g. how many unread messages in my email, and lots of other info. Win Win7 I either have to have that turned on and lose spatial memory associations, making my work slower, or I have to turn it off and then hover over a task bar entry to get the info I could normally get just from glancing downward. This all seems like a step backward in the productivity of the UI to me. But again maybe I'm just using it wrong.
Ultimately the problem with major UI changes, no matter how innovative or apparently helpful, is that people have almost always created potentially complex ways of working with the old design and may find it very productive. At the very least they may have developed habits of working that are very much ingrained and, even if not optimal, are still very familiar and enable fast workflow. The same arguments came up around the new Ribbon UI in Office 2k7. Some people got used to it very quickly and loved it, many, many others simply haven't upgraded since they find it annoying and limiting. I think splitting their userbase like this is not necessarily the best idea either, when they could easily just provide an option for it.