ExploderWizard
Hero
Truthfully, a referee can never set the pace of a game. They can only resolve the players' attempted actions. Unless the DM is playing an NPC, the speed of the game should ideally proceed irrespective of his or her responses. This is true for the same reason railroading a predetermined plotline cannot happen in an RPG, a DM can neither control how fast the players choose to play nor what their decisions will be. It's as simple as that.
The DM has no control over the pace of the action taken by the PC's but does indeed have control of the pace of activities and actions in the game world that are not within the PC's ability to control.
For example, if there were a humanoid lair in the vicinity of a human settlement, the DM decides how long it takes for those humanoids to organize and attack the settlement (assuming no activity by the PC's). The PC's can act in time, early, or be too late to prevent the raid depending on thier decisions. The pace of world events moves on. The humanoids won't postpone the raid because the PC's decided to go prospecting in the hills for a few days.