So... You know you canst a spell like... shadowbolt, or wrath, and the spell travels over to the enemy? Right now you're not allowed to do anything else as long as the spell is in transit. You get the message that another action is in progress. So... basically your casting rate is reduced the farther away you are to an enemy for these kinds of spells. Among other things, the ranged DPS reduction is quite severe.
You might experience the same thing with ranged weapons, but I've not tested it.
You might experience the same thing with ranged weapons, but I've not tested it.