Even if Haswell had the same IPC as IB on legacy code (which is wont), the new instructions and other enchancements (and IGP) alone would make it worth the upgrade in my opinion.
Oh, it's likely. I would like 6+ cores at or less than 95W.
The IGP holds little to no interest for me, personally. For what I do with integrated graphics, the current options are fine.
Now, I may be interested in them on behalf of others, though We'll see. Trinity is more exciting for me in that regard.
I am seriously thinking of building my own blade type chassis for Trinity and OpenCL computing, depending on how it performs, but if we get ~35W TDP desktop variants with full GPUs it will be on like donkey kong. I just have to research what it will take to split a PSU over multiple motherboards Darn, this appears not trivial. I'd really like to use one beefy unit and get it into the effeciency sweet spot rather than shell out for 4-6 PSUs and have all the losses and inefficiencies gained thereby.