Sentient Machine Race Lore/Material for game types
What if the "Bots" in the game are actually just a race of AI drones that have gaind sentience through one way or another and have their own civilization scattered across universes. Some of these are friendly and ally themselves based on their own accord (bots that fill in games), Some are completely hostile and have no care about intergalactic rules. These are the ones that can sneak into a battle and mess things up, attacking both sides.(Could be a game mode where Hostile bots spawn and attack everything.and if a main building gets destroyed that team looses)
This has been a long problem and all the other races decided they would all work together to prevent these hostile beings from causing any one any harm. Because of this treaty almost none of these machines could do any harm outside of the big games. Though if you want to volunteer, their various pilot positions on the perimeter that see a lot of hostile action.(co op games against bots)
This is inline with my rival bots idea. I think it maybe too much to ask for each bot to be unique. However a collection of personality types and play styles would make things interesting. In keeping with the lore and the teams idea you could have a handful of bots that are a little smarter, more tactical. They could be like the MVP's of some the other teams. They don't have to be 'bots' give them a character, some backstory.