@Siddeous
overacting much? If you don't use OneDrive then simply do not use it. It is a specific folder on your HDD that is not used by default, so it is pretty easy to avoid using if you do not want to bother uninstalling it. I personally happen to like it quite a bit and use it to sync my documents folder and desktop between all of the machines that I use, and it works great for that. I don't put any legal or personal documents in those locations (even I only trust things to a point), but as a sync tool it is wonderful and invaluable to have if you work across several different machines.
@JoseJones
You do realize that AHCI is a hardware configuration that has absolutely nothing to do with the operating system right? I mean, if you want faster performance (and have the money) there are plenty of m.2 and PCIe based solutions that Windows (or Mac, or Linux) will work just fine with while giving ridiculous amounts of throughput. Or if using high-end SSDs and 500MB/s is not enough for you then you can always tempt fate and go with a RAID0 setup and get 1GB/s across 2 drives (or 2GB/s across 4).
@Obi-Wan
No, you didn't miss anything. MS does not know how to count.
The 'real' reason is that a lot of newer programs scan for a Windows OS revision of 9x to prevent installation on win 95/98 machines, so they are avoiding that fiasco by moving to Windows 10 directly. They were also able to show with the win8 to win8.1 update that they no longer need a traditional update cycle in order to add features and functionality to the OS. With the move to Windows 10, I suspect (along with many others) that we will be on some version of win10 for a very long time (10+ years). Every year or two there will be a major service pack (feature pack?) to modernize the OS and add capabilities (similar to the Apple OSX model). The issue is that the core OS has not really changed since Vista, and it is much more of a pain to deal with the differences in APIs and security models between Windows revisions for the general public rather than having a single version for everyone that everybody gets upgraded to upon release via Windows Updates. This will keep everyone in the same app store, with the same hardware driver model, and the same capabilities across the board.
This also applies to other Windows products as well. Traditional Windows, Windows RT/ARM, and Windows Phone will finally all have the same core OS with changes to the UI to meet platform needs. The phone, tablet, and desktop OS will all have access to the same store apps, and the store will finally include some traditionally desktop-only apps as well. If they pull this off then it will be awesome... but if they screw this up then it will mess up everything for every platform.
MS is amazing at snatching defeat from the jaws of victory... I really hope that they don't screw this up.