In summary, there's no clarity to what the gear ratio change will be on performance for production 2015 Spark EV at this time. However, it's obvious that the improvement or reduction in range is directly related to YOUR duty cycle. It's also obvious that acceleration is not only a function of ratios versus speed, but software and hardware limitations as well. We all know that official range numbers are a valuable measurement for simple comparison sake, but that range/efficiency are very related to your duty cycle. If you travel at city speeds a lot, a higher numerical ratio will generally improve your efficiency. If you travel at highway speeds at 55 mph, the ratio change will likely improve your range slightly. If you travel at highway speeds at 75, the ratio change will likely reduce your range slightly. However, until a vehicle comes out with production software and hardware, there's no way to know for sure.
Agree that an individual's duty cycle is the key to range. For me, the Spark's better range at realistic freeway speeds would be the deciding factor. For what the car is, I can see little practical benefit to a faster 0-60 time, or even improving the 0-30 time. I don't think there's any need to compete even more with the i3; neither car provides the kind of acceleration that a true gearhead will want.
I doubt that many people are finding their BEVs range-limited in all-urban surface street driving. Speeds are too low and there's lots of regen. No, where most people have range issues is with part or all-freeway commutes and similar trips at realistic speeds, and IMO that's where the major emphasis needs to be to make BEVs more mainstream.
Most states have interstate speed limits of at least 65 mph, with most western states having rural interstate limits of 70, 75 or even 80, and actual cruising speeds in unconstrained flow tend to be 5-10 mph over the speed limit. Although it is often impossible to reach those speeds at the height of rush hour, outside of those times it's quite common. For me personally, I'd happily give up a second or two 0-60 (so equivalent to a LEAF or Focus) to gain 10 or 15 miles more range at 65+ mph, and retain or improve 30-50 and 50-70 passing accel. I regard the latter as far more useful in the real world than 0-60 times; I'm not interested in drag racing, but I do have to merge with or pass traffic regularly.