I'm with Ilario on this. This year we had about fifty countries participate, but there are many more which could take part in a "natural" features event. Take Georgia for example, like most ex-soviet states it has a non-commercial freedom of panorama, and very few old monuments in the cities where people live. The soviets destroyed pre soviet monuments and most Soviet era monuments have been melted for scrap. Compared to the UK there sometimes isn't so much that is unambiguously out of copyright and nothing modern can be used.
We also have new technology out there, lots of people could take videos of waterfalls, waves on a beach or even timelapse photos of a mountain snowcap through a winter. We could run a global event that focussed on that.
WLM could skip a year or it could focus on local events, we in the UK are considering looking at our gaps, and targeting our wiki takes events at towns where we have poor or low quality coverage of their listed buildings. Yes WLM has brought us some good images of buildings we previously only had poor quality images for. It has also brought us images of buildings that we didn't have any images for. But an awful lot of it has been additional shots of buildings that already have large categories - and that isn't going to give much improvement to Wikipedia.