Mobile OS should be only used for under 4" devices.
9-12" devices should have full OS.
9-12" devices shouldn´t be laptops at all. They should be touchscreen tablets. So I think the 11,6" MBA is a bad idea too.
If at least they would give the full internet experience for iPad (same experience as with MBP/MBA), I would consider buying an iPad, but for now it´s useless... (for me).
I should be working at Apple, then they would do things right!
Well, I for one am I glad you don't work at Apple, or we'd still be stuck with clunky tablets trying to run thinned-down versions of desktop OS and cell phones with huge physical keyboards and tiny screens unusable for anything but making phone calls.
As we know, Apple was working on a tablet project when Jobs had the genius to divert the hardware and software systems for a tablet into a cell phone. iOS isn't really a "mobile" OS, it was always an OS intended for tablet devices. It's just taking Apple some time to add all the features to it that makes up a "full" OS. If you recall the earlier days of desktop OSes, they were lacking in a lot of features that we now think of as standard on a desktop OS. You used to have to add a lot of utility software to a desktop OS in order to get a lot of housekeeping functions. With each generation of OS, more and more of those utilities kept getting incorporated into the OS itself. So give it a few more years and iPads will have a "full featured" OS. But so will the iPhone.
As for 9-12" laptops, you may not have a need for it -- as it happens, I don't have a need for one, either. Like you, I want a tablet device, unencumbered by a keyboard. But that doesn't mean that other people don't have a need for a 9-12" laptop. Someone who travels or is on the go a lot, and needs to type extensively, would probably prefer a notebook over a tablet, because they always need a physical keyboard. If you need a keyboard, then having the keyboard and screen in a single integrated unit is easier to carry around than having them in two separate, different-sized units like the iPad + bluetooth keyboard. Now, you might say people like that should just carry a 13" notebook, but again, for some, the extra portability afforded by a smaller screen is worth it.
I think eventually, tablets would evolve to a point where, as you say, 9-12" laptops aren't needed. But we aren't there yet, and in the meanwhile, I'm glad I have both a slightly under-featured tablet and a slightly cramped laptop to choose from, depending on my needs. And eventually, Apple's tablets and desktops/notebooks would run the same OS. But as Jobs demonstrated with Lion, that would happen not just because tablets gain desktop features, but also because tablet features get added to desktop OS as well. Jobs really does "think different," and that's why we are finally moving into a era for tablet computing, after god knows how many years of people waiting for them.
... I don't think so... 
