It would be absolutely horrible if any event could be added if there was enough popularity. The events available should be, in my opinion, an exclusive group. If anything could be an official event, then we may as well just make everything available officially. But if we do that you'll find the cubing community splitting into cliques, where people really only care about one or two events, while the major events (such as 3x3 and BLD) will lose significance. Your suggestion makes me think of the Olympics, which is now so overloaded with so many insignificant "sports"... the vast majority of people couldn't give a damn about most of the stuff at the Olympics, and this takes away from the significance of each and every event. Nowadays it's basically like "show up and play your sport then go home", rather than "if you win this you will be the top of the world amongst an exceptional and exclusive group of people".
Having a procedure for adding events might be helpful, but it would need to be a strict procedure, and it would have to be applied to current events as well to filter out the ones falling behind.