In a bluepost discussion on the official WoW boards member of development Greg "Ghostcrawler" Street hinted, that the developers at Blizzard were toying with the idea of allowing warlocks to have two demons for a short time of battle. Reason for the discussion was the reduction of the Doomguard-cooldown from 20 to 10 minutes. Apparently Blizzard wants to implement the possibility for locks to summon a permanent and a temporary demon at the same time with WoW Cataclysm, which could result in a bad class balance especially in the arena.
