A science fiction writer cum pundit you know of (and quote often) once postulated that defeating global warming would bring on the next Ice Age.

I skimmed the article you posted, and I didn't see anything about high altitude ice cloud formation as a result of all that extra H2 reacting with O3 to make water. Increased atmospheric albedo sounds like possible global cooling to me. Could be interesting... fact remains, we need the remaining hydrocarbons for other things in addition to fuel - like, for instance, plastic.

I wonder what a further ~8% reduction in ozone would mean for UV at the surface.

I also tend to think, given Hindenburg Syndrome, the systems are going to be designed as leak-resistant as possible from the get-go. We'll see.