As it is, if you are playing on the most difficult setting, you are sort of obligated to take the +combat related talents.
Frankly, in rpgs I usually don't care about efficiency or highest difficulty levels but more about flavor. Problem is, of course, if you play multiplayer, you don't want to suck in comparison to your friends in combat. But this is a question of game design: If the game rewards the non-violent solution by smart talking or sneaking with the same amount (or more) of experience, then it makes sense to take non-combat skills and talents. In Fallout 1, you could discover more about the background story if you had high science, convince the final boss to commit suicide or sneak to the big bomb and blow it up. In Shadowrun/Dragonfall, you could find out much more about the motivations of the dragon if you had high biotechnology or magic. To some people, finding out such secrets is much more rewarding than being good in combat.
