For me, the big issue is range. I like long rides, and current technology does not support them. I'm not a motocross rider, but if I were, I think I'd be pumped since short, silent sessions near the charging station are already possible.
While we are talking about these things, another issue is lack of a clutch. A friend of a friend raced endurocross on an Alta, and said he was petrified of some of the obstacles with only throttle control to rely on. Sure, they make instant torque, but the clutch lever gives a whole different set of options for control, which he really missed. I imagine a clutch lever could be made to work with software only (no actual clutch mechanism, just using the position of the lever to change how power is delivered). Does anyone else see this as a problem?
What does everyone think of the KTM battery lease proposal? I think it is a deal killer.
One last thing. I spend a ton of time on access issues, so I'm really aware of how sound is a problem for OHVs. But with that said, I've gone away from ultra-quiet exhausts (I aim for 90-92 db now, which is still under the legal limit) because so many mountain bikers and hikers use earbud headphones while recreating. I imagine there is a whole new set of user ethics to develop with quiet, and potentially quick, electric motorcycles.