I agree that the new gas cans are awkard to use, and result in more spilled gasoline. Most of them are also not drip proof, and rain water can get into the can unless the spout is tight. A tight spout lets the cans blow up like a balloon in hot weather. The theory of the EPA mandate was, I believe, to reduce evaporative gasoline emissions during storage with the new can designs , by eliminating any vents. Of course, we probably spill more gas with the new designs than ever evaporated with the old designs. Even worse, if your can has a " push on nozzle to pour" design, any pressure buildup in the can will cause gasoline to spurt and spray out of the nozzle, and all over your engine. That's an irresponsible and dangerous design, in my opinion.
On the cans that are unvented, I leave the caps a bit loose, and cover all of the cans with a tarp to keep out rainwater, and protect the plastic cans from sun UV damage. I also recently bought some caps ( eBay, I think) that fit on Blitz built cans in place of the pour nozzle, so you can just use a funnel to pour out gas. Golf Tees make good removable vent plugs.