You know what would be nice? External event sheets. Sure we can call python scripts and stuff, but event sheets are still limited to the construct program. Wouldn't it be nice to use Construct's native event sheets as external text files to be imported at runtime?
To be able to include a custom level template along with the EXE... and have this feature be native to Construct, would really beat the hell out of INI files and python scripts. In your games, you could write functions that could be called by a modder through external events. Want the space background instead of the water background? Change the line of code in the template, and have the layout's events build the level per your commands for that choice.