I bought the MBA for the eco system firstly, and because it is so cool secondly. Take away the eco system, and you are left with something that just looks cool but doesn't work well.
Now, with that said, this is my first Mac, and while I love it to death...I'm worried the Mac App store isn't going to take off (pretty meh right now). This would be a real damper on the switch.
Maybe I need to break out my Xcode and help!
You do realize you can get software for the Mac other places than the Mac App Store. If it's meh, look elsewhere. I still buy most of my software outside the MAS.
I suspect, however, that over time more and more developers will add their wares to the MAS.