As far as the GUI being lacking (such as the so far less than pathetic Start Menu), it's not as if MS doesn't have the tools to make this balls-out amazing. I believe that what we are seeing (or not seeing as the case may be) is a Management decision to NOT make the Start Menu awesome. MS has politics like any other large organization and I promise you there are powerful voices who are still butt-hurt over the idea we are going back to the Start Button concept at all, and they'll be damned if they are going to make it fantastic so the whole world can say, "See, Windows 8 was dumb, THIS is how you should have done it from the beginning!"
I'll be amazed if the Start Menu in W10 is dramatically improved from it's current lame state in the final release. This will make two groups of people happy - the Management idiots at MS and the owners of Stardock.
** P.S., Yes, I am taunting MS on this. I DARE them to prove me wrong. They don't have the stones.