I feel like esports have the potential to be enormous but won't reach that until standard formats are established. I'm thinking some FIFA, FIA, IOC, etc., -type group releasing spec sheets and FOSS client/server implementations that developers then port into their own engines. The idea being that the barrier to entry is so low that anyone can experience the game. It's not a coincidence that the most popular sport in the world is also the most accessible.
This is usually the part of the HN comment where I plug my startup that solves the exact problem, but sadly that's not the case today.