Depends on how you look at it: If you think that the changes to the kernel in Win 7 ( I take your word for it that they exist) are so significant and could only have been implemented at the time when Win 7 was released, well and good. But most people see the XP-->Vista "upgrade" as a broken failure.
You don't have to take my word on it. Mark Russinovich, formerly of SysInternals, has written numerous in-depth articles on the matter which you can find on TechNet.
I'll definitely give you that Vista is broken, though I will say that the upgrade process worked flawlessly for the several I did. Vista is crap, there's certainly no argument there. Like 7, it does have a number of internal enhancements, like the new security model for drivers, but any gains were incumbered by what some would argue is sloppy programming or over-intricate dependencies.
My view is that Win 7 is what Vista should have been.
I'll concede that, as well, given Microsoft had over a half-decade to work on it.
And MS knew it, which is why it rushed out Win 7 when sales of Vista were poor, in much less the time that it went from XP to Vista.
And padded their Vista licensing figures, and so on. Yeah, they know they have a turkey, which explains the very short support life-span of Vista. What really pisses me off is the obvious "phuq-you" Microsoft gave to people who refused to go to Vista in the form of no direct in-place upgrade path from XP to 7.
