Was just thinking today that when thieves do Propaganda on enemy, they are trying to 'convince enemy peasants, military, or wizards to revolt and join your province.'
Now since Scientists are also part of enemy province, why not extend Propaganda to include having a chance to get enemy scientists from the enemy? Keep it at a low chance to get a scientist from enemy so that it's not too overpowered. A rogue would need to spend a lot of stealth doing propaganda if they want to have a shot at getting a scientist from the enemy.
This opens up a new avenue of game play for Rogues by allowing them to have a different way to get scientists for themselves in addition to Scientist spawn boost from Revelation and Labs.