Yeah, neat idea. Although reducing culture and increasing income sounds kind of counter production. Lower allegiance means lower income. Other types like this would be neat though like the stronghold idea above.

Gonna use your little chart, Giro, and add to it. Hope you don't mind, because I'm using it because I like your ideas. =P


Maybe:
Normal- Planets start out this way, and are like how they are now, with no bonuses other then planet type bonus.
Caste System - Increase fleet cap 25, but decreases build time by 20%.
Serfdom - Increases build times 20%, but decreases culture 30%.
Slave Labor - Can sacrifice population for instant build of structures or ships.
Wage Labor - Increases allegiance by 10%, but decreases fleet cap by 25.
Stronghold - Decrease income and population by 50%, but increases tactical capacity by 8, and planet health by 50%.
Market World - Increased trade and resource income by 50%, zero tactical slots overall.

Also:
Switching labor systems would result in a one minute of anarchy. During this time, building speeds are reduced 20% and income is reduced by 10%.

Switching from labor systems costs around the same as designating a capital planet.

Hells yeah!