I think AC charging with an aerodynamic fairing and about 20kWh of battery would make a Zero a touring bike.
DC charging is obviously desirable but accomplishes nothing in the vast tracts of North America and Europe where 220V AC is common and much easier to connect a Zero to (via J1772, Mennekes, NEMA 14-50, Tesla Destination plug, etc). DC charging also always requires a lot more money for any EV maker to support in terms of R&D, per-vehicle equipment cost, and potential failure handling.
You know what's really interesting, though? Electric motorcycles occupy this transportation niche where, because they consume half (or less) of what a car needs per mile, AC isn't so much slower than DC at range recovery that it impedes touring.
A 2018 Zero SR or DSR with a Power Tank has 18.0kWh of maximum capacity (~15.7kWh nominal) which at 100Wh/mile would make for a 150 mile range bike. Reducing consumption to 70% of that via fairings pushes the range beyond 200 miles, or alternatively adjusts the recharge time for a given distance by the same factor.
Terry predicted all of this a few years ago, and it has been terribly patience-trying to watch it unfold slowly, but it will happen.
I think we'll see in 2018 a Zero with Power Tank, maximum DigiNow investment, and a fairing that IS worthy of use for touring.
I'm personally aiming for 2019 unless I can unlock my personal budget or get some project-level investment going sooner than that.