Wiremod doesn't really count, the whole point is to build stuff, so that's pretty similar to standalone programming.
To clarify, my idea sounds like this:
Have a 2d side scrolling game (maybe upgrade to 3d fps if all goes well) shooter where you have to advance though a somewhat linear level killing enemies to advance to the next level. But some of the enemies are robotic, and with say, an emp grenade you can disable them so you can safely go up to them and reprogram their AI (which would be lua, edited in an ingame text editor) and restart them so that they will now help you fight. And I'd probably make the game so on the easy modes the programming isn't needed to win, and in the hard mode it is, as I'd probably try to make programming not necessarily required to play. (as to expand the playerbase)
