Summary:
1) Kill Windows RT
2) Make current and future legacy programs more touch accessible. Thus, little need to make metro / Windows store apps. Not like there's much in the store.
Ok, this sounds far less questionable now.
I still disagree though. Culling the Windows Store would remove the security of having applications that are approved, and not as potentially damaging to your system (back to removing ad bars from your computer illiterate friend's tablet now). It would also reduce visibility for new applications, as the store will often feature them, and people's feedback can be used to promote compelling software. You would also be once again screwing over all developers that have made any investment in the ecosystem so far... and that's really been done too many times in the past already. You'd also lose the ability to leverage Windows development to benefit the Xbox. You would also probably fall into the Android problem of developers not bothering to sufficiently adjust their applications to function across different device types (because it's not like anyone's there to reject it anymore).
Then there's the fact that pretty much any benefits from what you're suggesting would also be accomplished by this:
...but without all the negatives listed above.