Actually, having let that one go a few times, I've found the 'Super Race' Mega event, even in the long term games I tend to play, doesn't have all that much effect. I haven't actually looked at superrace on a turn per turn basis, but the advantages accruing seem to be less, statistically, than you get from having a few surveyors zipping around.
My most recent game seems to have randomly picked up 'no additional anomalies', but it seems to have also toggled mega events off, so I haven't had a chance to see it compared to a game where I don't get to survey yet.
Now, I *like* the way you think about jagged knife. *That* would be a more interesting mega event. I would even go so far as to give the Jagged Knife 'inherent' Mind Control Center ability (Would explain a lot wouldn't it), to make you pay attention.
Pirates would be better off if they were generated more consistently. Every time I've ever had them, it's a simple strategem - sit back, make som fast colony ships that can out-run them and colonize a planet, and eventually get over their tech curve, strap arnorian battle armor on, and kill them all in a few turns. If they were (slowly) generated, and upgraded technology based on something in the game (Unhappy planets maybe?), that would be a more interesting Mega Event.
Actually, it should work like this - Pirates and the 'spy' event should be combined to a 'special' AI, the Pirate cartel - maybe even combine the jagged knife in with this.
The Pirate 'income' is based on the income lost to corruption in the various economies, the 'decommissioned' value of ships they destroy, and (if we combine all three), the later income of the Jagged Knife worlds. They have access to all researched trade goods at all times (as if they traded for them).
Their technological access is based on where a given ship is built - until Jagged Knife they can only get ships built (As for cash - criminals don't let criminals use payment plans) on unhappy (<40%) worlds with starports, plus anything they can steal using spies (Done the same way as the normal AI - percentage of income+bonuses. Of course, they have to steal any technology for bonuses - {G}) as 'common technology'.
Such 'bought' pirate ships will of course not attack other pirates, nor will they attack ships generated by the same world they were built at (Not empire, planet) unless they attack him. Everything else is fair game - maybe even have some AI tendencies towards "Privateer", i.e. A tendency to move towards antagonist foes of the original empire given the opportunity.
Until of course Jagged Knife, where our new AI player moves from the small time nuisance to the big leagues, pooling the technology from each planet he steals from an empire.
The Pirate AI should be a specialized version of the regular AI - you should be able to donate cash or ships and 'buy' attacks on other civs - but of course since the Pirate AI is buy default at war at all times anyway, you never have 'make peace with' - you only have 'paying protection', 'at war with', and 'paid to attack'.
I think you could combine these three mega events into a *much* cooler more cohesive whole than any of them are separately.
Jonnan