The Barbarian (and FotF) are specific exceptions to the general rule about fatigue.
Anything else that doesn't list a duration for the fatigue effect means it'll take 8 hours of complete rest to get over.
Touch of Fatigue for instance only has the fatigue effect last as long as the spell's duration, thus it doesn't require rest.
As far as standard fatigue effects like sleeping in medium or heavier armor go, I can see several DMs putting house rules in place to help move the adventure along. Alternately, there are plenty of spells and other effects to negate fatigue.