Intent or recklessness, great.
Since his intent was not to shoot, now you are left with recklessness. Since there have been many gun owners, over the years, for whom holster-less carry was normal, IMO you can't establish recklessness simply because you (and I) think holster-less is a bad idea. You would need either statute or case law that said such carry met the level required for recklessness, as opposed to simple carelessness. These are not the same.
Some folks have thrown "Plaxico" around. Please bear in mind that Mr. Burress was not licensed to carry in NY. I am not sure if his gun was legally owned in NY. His charges did not directly result from the discharge of the weapon, but from the fact he was carrying it in the first place.