I suspect that if strategies were told in advance whether they are going up against themselves then Cliquebots would do a lot better.

It might also be interesting to see what would happen if the bots were allowed to either remember their last N scores and/or win/loss record for the last N games, or know how many other bots of their type exist in the population. I suspect that "if I'm a member of a small minority do X, else if I'm a member of a large minority or small majority do Y, else do Z" would be an interesting class of strategies to look at.