I really wish there was a way to import a map that you played on previously and start a new game from there. the ruins of a lost civilization. would be a nice alternate start map/mode. of course there could be an option to dismantle the ruins and get some bonus material, or rebuild it as best you can by adding on to the ruins.
These can be user made, or generated buildings that are not completely built. Basically buildings that if you built some of it then hit pause building, that is what a ruin could look like. This would mean that there are many variations of the same building at different stages, so its basically an infinite variation on the start of the game even with just the vanilla template set.