With regard to the option of "diversify", I've been thinking:
Biologist: 15% population
Builder: 20% reduced upkeep
Excavator: 5% bonus artis
Explorer: 10% more scan
Fixer: 10% more hull
Governor: events 2x more likely
Hacker: 15% hacking strength
Merchant: 15% more cargo
Miner: 5% more minerals
Physicist: 10% more shields
Raider: 15% more raiding
Saboteur: Disables an structure, reducing it's effectiveness by 50% for 4 hours
Spy: 10% more cloak

Some of the more "exploitable/useful" professions have been nerfed more than others, namely fixer, Physicist and saboteur.