Rivers are a messy case. Blocking swimming and flying over them doesn't make a lot of sense if you can fly over lots of other stuff. While they are often used to protect areas, I'd make the case that in most of the bigworld map, allowing people to fly/swim over them wouldn't be that big a deal - sure, there is a bridge down a ways, but letting someone fly over upstream shouldn't be a problem. After all, it then makes zero sense that if I follow a river down to the sea, I can swim or fly over the shallow water to get around the river, but not over the river itself. That said, there are certainly a few places where it really needs to block movement. The problem is that in many of those, it can look artificial (look, a nice ring of river). As a note, and this includes ethereal travel, any changes to the blocking of spaces has to be done on a map by map/space by space basis. IF we change the archetypes to suddenly allow swimming and flying over shallow water, I think we'll find many maps just got broken. Same for ethereal travel through walls. That said, I could certainly see someone writing scripts (or updating the java editor) with something like 'allow ethereal travel on walls on this map' or something, so that its just a simple 'is it ok to do on this map or not' type of update. But I do think giving someone permanent or at will ethereal travel will be very powerful, even with some of the limitations. The fact is that lots of maps have enough wall space where an ethereal creature could effectively hide out away from any attackers. I'd certainly much rather temporary items (potions) be added first and see what that breaks. I'm also a bit reluctant to add tons of new movement types. After all, at some level, the movement type is the same, what is different is that some things may move through spaces better than others. So rather than adding a desert movement type (or camel), I'd rather desert have a high enough slow move penalty to make it very slow to move through, and then give camels some ability to ignore that (built in desert movement skill or something). Similar for forest and jungles - I'm not sure I want a new movement type, vs making it painfully slow enough you have the appropriate skills.