In 3.5e, many invocations had durations but since you could almost always recast them without anything bad happening they were often infinite. In 4e, most were encounter or daily so you couldnt just recast them.
As for at-will disguise self. That would be cool in a doppelganger/chameleon way. Making it short rest would remove any "replicant shuffle shenanigins". One person stuffed in a closet per hour.
As for at-will disguise self. That would be cool in a doppelganger/chameleon way. Making it short rest would remove any "replicant shuffle shenanigins". One person stuffed in a closet per hour.