They are mazes indeed.  I'll call them "an advanced class in more-complex multipolygons," especially with all the history associated with them.

Still, we seem to make them sturdier, more accurate (punching out inners in correct ways) better tagged and up-to-date with changing tagging tastes.  For anybody who keeps track of this (mentally and internally with OSM's history and changeset archives) it is both complex and explainable, but more of the former!