My suggestion would be to mod the strength of the pirates down to fit the gameplay with your friends. There are a couple of threads here somewhere that show how to do this which is not as complicated as one would think.

I would be fine with your suggestion overall, but don't think it will happen anytime soon.

Personally, I'd just play with the pirates off.  I really don't know what they would add in a game pitting friends against friends.  How would you ever know who truly "won" the game with an element like pirates in the mix?

Pirate strength is fine.  Pirate frequency is not.  13 minutes between raids and 5 minutes between missions causes problems now that the pirates are much stronger.  Increasing both timers to 15-18 minutes would be more in line with their current strength.  Also, the AI bounty bug isn't helping matters.

Pirates are there for FFA.  They don't really work in locked team games, as they just turn into an extra military force for the team that's winning.  A normal raid, two 10000+ missions, and your normal fleets will pretty much end a 2v2 game right there and then.  I fully agree they should be turned off in any locked team game.

pirate frigs have 21-24 armor...equiv. to a full defense starbase.
they also have 2k~ish hull, just a couple hundred short of a fully upgraded HC.

pirate turrets have 34 armor...and 7k hp...and 100 dps....each basically a starbase with all defense upgrades.

now imagine a late game raid bringing 40-50 pirate frigs to your base...

oh, yes, and the turrets are perfectly capable of murdering strike craft...