Dual core A15, if that's what the A6 turns out to be.
My i4 feels slow. If the 5 had a dual/quad a9 (an A5, A5X, or some variant), I wouldn't touch it with a stick.
Pardon my french, but the other features are... err, bovine excretion... to me. Lightning is a BAD thing, LTE's nice, but not essential, Siri is pretty impractical, the longer screen is... nice, I guess, and all the software improvements are nothing compared to what we already get from the appstore/cydia.
Seriously, if it weren't for the major hardware upgrade, theres no reason to pay extra over a 4S.