I've been thinking on these lines recently too, and maybe the game could be to allow others to experience the fun you're having in building these rules and watching the outcomes? Letting them author the rules, and watch the outcomes. Or letting them manage and upgrade the bots, sorta like an overlord who doesn't actually chop wood etc.
This is kind of a nebulous idea (and definitely not new), but spawns from the fun I've been having the past few weeks in writing a bunch of simple rules for cities to attack, ally, trade with each other. Watching kingdoms evolve, alliances form and break, funny situations like a rock shortage eventually triggering a massive war among all kingdoms, was fun. It might not be as fun for a passive observer, but as the author of the rules, the feedback loop of making changes and watching the emergent outcomes was pretty neat (kinda like programming, heh). But it is a scary path to go down, if the intention is to market it as a game, because it doesn't look or sound like any "real" game.
On a different note, Dwarf Fortress is ripe with such emergent outcomes. On another different note, Robocode is quite fun where you author bots and rules and watch how the bots fare against each other.