You are going to see Windows 8 tablets focus on the 10 and 8 inch size.
You are going to see Android focus on the 7" size.
For a couple of reasons
1) The 7" size is focused on downward price pressure. The Amazon Kindle Fire (followed by the Nexus) caused people to associate small tablets with cheap tablets. Furthermore 7" tablets are cheaper to make for the screens are cheaper to produce, as well as requiring smaller batteries. People see 7" tablets as internet consumption, movie consumption, book reading, and games. Thus people see 7" tablets as toys and expect them to be priced as such.
Android is cheap to make with very low licensing costs. You are able to hit those price points with Android that you would not be able to hit with
2) A 7" size forces a redesign program to be effective in the space. You are not going to dock a keyboard or mouse with a 7" and make it a netbook. Android does not have backwards compatibility, so it isn't going to even to try to recreate the wheel instead the programs are going to always touch design instead of trying to take an old x86 program and tweak it. If the "baggage" of windows is not going to be useful, then get rid of it.
Windows brings nothing to the 7" space, while Android brings a lot to the 7" space with preexisting phone apps working well with touch being scaled up for the 7" tablet size.
----------------
1) 10" tablets on the other hand from quality brands (and not no name chinese tablets) have not done a race to the bottom. The oems do not want to do a price war ruining their margins and thus the price for 10" android tablets are already about $300 dollars
If the price is $300 dollars for an Android Tablet it is not a hard sale to get a person to buy a $350 or $400 Windows Tablet (I am ignoring all windows 8 tablets with 32gb of storage for 32gb of storage is dangerously close to the amount of storage you need to make windows work).
2) 10" tablets are the smallest size you can be "productive" with a tablet. You have enough space to write a document. 10" size means you can fit a normal usb port on a tablet if you are not obsessed with thinness. 10" tablet means you can have an "almost normal size" keyboard approaching 85 to 95% laptop key size. 10" tablet is actually large enough to do multi window and have something useful on each side of the tablet. 10" is big enough that a scaled up phone apps should be redesign to take advantage of the greater space. 10" is big enough you may want to use an internet browser instead of some form of dedicated app.
All of these things are things that leverage Windows real nicely. Windows advantage is that it works with peripherals. Windows can do true multitasking with snap. Windows 8 (since we are talking baytrail) works with all your old programs and as well as working with many new apps. Windows 8 works with flash (even though this is a less of a problem now a days) and normal desktop websites (some mobile websites are pure crap.)
Windows 8 has Word, Excel, Outlook, and Powerpoint (in that order of importance.) (hell many windows tablets are coming with a free version of word, excel, and powerpoint but not outlook)
----------------
8" tablets are going to be an interesting market for Windows. The way you use a tablet differs completely if you use a 7 or 10" tablet but an 8" tablet can blend those different styles of use and be a jack of all trades expert of none.
You are going to see many tablets that are android use baytrail as well, probably after christmas though.