For Windows devices they want to run all their apps and connect to their networks without problems. They want good performance for their applications and graphics. They don't care about TDP or how the CPU maker achieves it, they are just concerned how long it lasts.
This is why the Y Ivy Bridge has has virtually overnight forced manufacturers to abandon the ARM based RT tablet and build new x86 designs. x86 is where all the action will be this year for Windows tablets. And since x86 also runs Android and other forms of Linux there's is a very good possibility that users can run multiple OS'es on the same device.
I think Clovertrail is what killed WindowsRT but the 7W Ivy bridges and 13 hour Haswells will probably turn some Android tablet users back to Windows. So Defense turns to Offense as in all good football plays ;-).