About the only significant difference, I expect, would be a higher top speed-on a downgrade.
I was going to suggest, that a far cheaper and easily reversible way to test this, would be to get higher-profile tires, to lower freeway RPM.
But that got me wondering about aerodynamic drag. Normally a higher profile tire would, by raising a car, very significantly increase drag. But with the LEAF's smooth underbelly, it might not increase drag a great deal (though increased lift might significantly affect handling if you changed the final drive ratio enough, AND found a grade steep enough to produce very high speeds...).
I owned a Citroen DS21 with an (almost) smooth belly plate, and a hydro pneumatic adjustable suspension, giving it several inches of ride-height adjustment. I don't recall ever driving long distance on the high setting, to check for how much fuel economy or top speed was reduced, though...
no condition is permanent