Ideas need to be prioritized. Getting the Nim syntax skin idea out there would be a very significant advocacy advance to help put more fuel in the tank. According to [PYPL](http://pypl.github.io/PYPL.html), Python has about 15% market share, and other [off-side rule](https://en.wikipedia.org/wiki/Off-side_rule) languages hardly register. Lots of people who previously skipped Nim because they're allergic to the indentation syntax would suddenly jump on board. As this skinning feature would be pretty unique to Nim, it would be news-worthy on the general programming sites. Instead of being on one unpopular side of the syntax Holy Wars, Nim would make news as the peacemaker that makes those wars obsolete!
Auto-converting from one syntax to another, caching AST for cross-compilation, and other ideas - possibly useful, but not potential game-changers.