I don't get why people keep thinking Haswell will be such a jump from Ivy Bridge. The MCM upgrade that'll be featured in Broadwell/Skylake will be much more noticeable - all Haswell might offer is slightly less power consumption, which is nice but not dealbreaking (imo).
My big ones:
-Less Expensive (who wouldn't want that

)
-More battery (again, who wouldn't

)
-Software bugs worked out (faster and more efficient GPU scaling)
-A 13" Option
-A 32GB RAM option (hey, maybe I WANT 16 VMs up at the same time)
That's pretty much it, though. Like that, it'd be pretty much perfect. I'll probably pull the trigger now, because the first two are things people always wish for, the third really isn't a hardware issue, the fourth doesn't matter to me, and the fifth is more of a pipe dream than anything.