The question is: how important is consolidation as a feature? Surface Pro doesn't let you do anything that you couldn't already do with your laptop + tablet. That's a crucial point in comparison to the iPad, because iPad was better for on-the-go media consumption (or on-the-couch media consumption) than either a smart phone or a laptop. The value-add in the Surface Pro, then, is just consolidation.
With existing technology, that consolidation involves a lot of compromises. My MBA + my iPad Mini may be heavier than a Surface Pro, but combined get 14-15 hours of battery life, which means I can pretty easily leave the charger at home. Can you leave the Surface Pro charger at home? With only 3-5 hours, no you can't. The combo gives me a choice of two screen sizes (13" and 8") as well as the ability to use both screens at once (say looking up documentation on the Mini while coding on the MBA). And the MBA has a far superior keyboard and trackpad.
Does consolidation outweigh those other advantages? I don't think it will except for a narrow class of people. Surface Pro is really threading the needle--targeting users who need more than just a tablet by itself (which most people don't), but also don't need a portable screen bigger than 10" or a good keyboard.
It's much simpler and more convenient to use one device than two, which is why people no longer use Palm PDAs. This doesn't mean Surface Pro is the best form factor for everyone. Surface Pro has about the same battery life as a MacBook Air, but it could be much longer if the keyboard had a second battery.
That was the idea behind the Asus Transformer, and in hardware terms, it works very well. (The software is another story.)
Of course, the resulting weight would be more like carrying both an MBA and an iPad as well, but at least you wouldn't have to pay for two motherboards, two screens, two keyboards, two sets of RAM etc.
In passing, you don't get longer battery life if you use two devices at the same time, as in your example. And if you search on one screen while coding on the other, the Surface Pro is dramatically better. You get real multi-tasking and two apps side by side on the tablet screen, and you can copy and paste between the tablet and the desktop, or use a Share charm to send stuff from one app to another. Basically, you're using the iPad mini like a book, aren't you?
With existing technology, that consolidation involves a lot of compromises. My MBA + my iPad Mini may be heavier than a Surface Pro, but combined get 14-15 hours of battery life, which means I can pretty easily leave the charger at home. Can you leave the Surface Pro charger at home? With only 3-5 hours, no you can't. The combo gives me a choice of two screen sizes (13" and 8") as well as the ability to use both screens at once (say looking up documentation on the Mini while coding on the MBA). And the MBA has a far superior keyboard and trackpad.
Does consolidation outweigh those other advantages? I don't think it will except for a narrow class of people. Surface Pro is really threading the needle--targeting users who need more than just a tablet by itself (which most people don't), but also don't need a portable screen bigger than 10" or a good keyboard.