Walkthroughs for custom maps.

Perhaps a prize pool could somehow stimulate interest. If I'm not mistaken, there was one in FirstBlood. But that's already in the realm of fantasy.

The issue isn't the prize pool, although it does create hype and motivation. The issue is the community. When there is one, it can be motivated, and you can find players within it who would be willing to play. When there isn't one... it's difficult to get anyone interested in playing something that no one is interested in. The difficulty of the map isn't crucial. As an example, consider running a marathon. Once, it was something only a few people did. Now, the healthy lifestyle community is so developed that thousands and tens of thousands of participants run marathons. And that's a very challenging distance. The main thing is to have a community where this is interesting.