I thought one of the main ideas behind having the phones, tablets, and PCs running the same Windows kernel was to ease & promote app development across these platforms. It would certainly be a big improvement over what Apple has. I don't do WP development so I haven't paid much attention to it but it seems like Microsoft is silo'ing WP from the rest of the devices stack.
If it were up to me I'd have one apps store (filtered based on the type of device connecting and its capabilities), one developer license (for all device types), and one runtime/SDK/IDE (that covers all devices types). Develop for one type of device and at least have a head start for another type of device. Also simplify the developer experience by only having to join one program in order to get your apps to market.
From the look of things at this juncture WinRT devices are going to be left out in the cold for apps just like the original WP. Microsoft will of course be repeating the same line of "all of the important apps are there". And you know I could live with that if their first party apps were actually any good.
At this point I believe like many of you that Microsoft really needs to make the first year free for devs.