What's this about spells having secondary effects?
From what I got from this, it sounds like they've made elemental magic more realistic. So instead of fire just burning the enemy you shot it at, it will now start parts of the environment on fire. Possibly jumping between enemies? I don't think spells will necessarily have a "secondary" effect, they'll just be handled more realistically. But I don't think the effects will combine realistically. Just stack.
Oh, and not too happy about this "low fantasy" news. I didn't have a problem with Oblivion, exactly, but making the game less out-there is a step in the wrong direction, IMO.