No one's expecting very much from Haswell CPU side but, AMD are pushing towards more utilisation of the GPU for CPU duties, and Intel is going the same way, not sure Intel are ready for any new CPU/GPU architecture which will leverage the power brilliantly, but I'd expect quicksync style features to be improved, more widespread, and more supported. Likewise the quite probably on die memory will potentially give huge improvements in speed for things that can utilise the CPU.
IE a lot of the effective CPU power increase could be from the GPU, so the more powerful GPU could be very useful to everyone.
Then you've got a mature 22nm process, and a mature chip that has spent more time being designed for 22nm from the ground up, and with tweaks/improvements based on their experiences with Ivybridge, so even if IPC is similar, it could clock significantly further.
I wouldn't write off Haswell yet in terms of CPU power, I'm also not completely convinced Intel has been completely honest with where the "mainstream" range will be.
They've said mainstream is basically dual channel, quad cores, 6-8 cores would be wasted on dual channel mem but triple/quad channel mem is simply far to expensive for your average "dell" box. I think we might actually see 6-8 cores in a "upper" mainstream bracket, as yet not really talked about.
Think of it like 285gtx(hex core Sandy, expensive boards, expensive features, too much) high end, 9800gtx(quad core, dual channel cheapy) midrange, moving to a 580gtx/560ti/550ti setup.
Maybe pushing in a upper midrange platform, not as cheap as a 2500k, not as expensive as a hex core Sandy.
That's what I'm hoping for anyway, I can understand Intel's main platform not being more than dual channel/quad core, but throwing away octo dies as a cut down part isn't hugely profitable for them either and the price of mobo's/chips puts off most people. A cheaper tri/quad channel, hexcore die that is cheaper to make and cheaper mobo's would sell pretty well right now.