THis is looking really cool and it definitely fits with what I think would be cool to see on the market place. More complete game examples that pull from existing games as a base.
One thing I do note is that as a level designer, my concern is not to have complex geometry with configurable parts. Honestly all I want is some tiles I can drag into the scene even if it means hand placing them all I dont care about that. I never feel that the building of geometry to be the bottleneck its more about deciding what I need and how to make it play properly that is slow. Build stuff is usually extremely fast once I know what I need.