The 10W chip will be a weaker SKU, probably even weaker than current 17W IVB CULV chips. They are not magically lowering the TDP from 17W to 10W for the next generation.

Cortex A15 will get the benefit of pairing up with A7. ARM says on average the energy consumption should be about half, compared to Cortex A15 alone.

Also Haswell is rumored to cost 40% more than an IVB Core. That's close to $300 for a CULV. That's simply not sustainable when it comes to the new market that is forming for tablets. $300 is more than the whole BOM for your typical $500 tablet. I doubt you'll see that chip in anything cheaper than $800, at a time when you get "good enough" tablets for $200 whole. Intel's competitor to ARM simply isn't the Core line-up. It's Atom, for better or for worse.

And as I said, Intel will lose not because of lack of expertise in making chips, but because of an unsustainable cost structure and business model (they now have to compete against several ARM chip makers at once, including Apple). The fact that they also have no momentum or market share in the mobile market doesn't help.