Especially since it's so unnecessary to implement it the way they have. And how effective SB will be still remains to be seen.
Unnecessary? The overall design is actually pretty open and flexible. If
you want a trusted boot sequence, it could be done a helluva lot worse. Yes, the UX is clumsy, but (for UEFI implementations that do have key management features), you actually have full control and quite a bit of flexibility, and you aren't limited to One Master Key To Bind Them.
As for effectiveness, we'll see indeed. There's no such thing as perfect security, and if you can escalate your exploit-code to kernelmode you'll probably be able to defeat SecureBoot easily. And UEFI is a big and complex beast, so there's probably exploitable bugs in it. But the key architecture seems sound, and security is about a mix of breadth and depth - and SB does raise the bar against pre-OS attacks.
I do predict a lot of people are going to work hard on attacking it, though, since it's such a hated featured and high-profile target.
A computer can officially only run Windows 8 if it has the very same "new UEFI secure boot platform", so it doesn't matter what else I might be planning, if my plans included Win 8
While UEFI+SB might be a requirement to get the "designed for windows 8" certification, Win8 works just perfectly without SecureBoot, and it doesn't need UEFI either, works fine with BIOS booting.