How many knowledge skills do you think is the right number in a typical setting? You need enough to differentiate between different aspects of the setting, but not so many that no one invests in them. My experience in SW is that knowledge skills are only taken at character creation, and the high intelligence character does most of the "knowing".
What do you think of a talent like this?
Learned Professional
Tier 1, Ranked
Pick a non-knowledge skill and a related knowledge skill. Ranks in the non-knowledge skill also count as ranks in the related knowledge skill.