It's not clear how to distinguish between a "create" and "move" when posting an entry to a collection. There's mention of the CMIS-removeFrom header/arg which could be used to distinguish (an approach I personally dislike), but this arg is optional anyway.

An intended move on an object that does not exist results in a create. Another option is to use PUT to change the parent folder id. Although this would require other changes to the spec to support parent id on docs as well as the fact the parent id is read only.