Can someone explain the talent system in star wars saga to me?
Basically they broke down what you would normally consider class features / abilities / spell slots etc. into groups of "talents". You could pick new talents every other level from the groups of talents your class or prestige class had access to (usually 3-5 groups).
The important differentiator in Saga was that most of the talent groups did not have 'deep' trees. There were hardly ever more than 2 prerequites for any talent in a group. So if there were 6-10 talents (abilities) in a group you would hardly ever have to spend more than 3 talents to get a keystone ability in the group (there also could be more than 1 per group because of the shallow trees). Even entry talents (no prerequisite) could be useful to characters at any level, 1-20.
This structure made multi classing work really well. In fact the classes were more building blocks than anything else (gave you access to certain talent trees) and the system never added anything beyond the 5 base archetype classes + pretige classes.