Still the developpers could find ways to have different outcomes based on how long a player takes to end a quest (specialy the main ones that usually rely on the fact that the main character has a main role in a world changing event), or find a way to push the quests of the various chapters to completion before the depleting of all quests (from a narrative point of view it means to create "interludes" that justify the fact that the player can spend time in completing side quests) or made the side quest influence the main one.
Please no timed quests. Those are the worst.
They already exist. The biggest one is Waukeen's Rest - if you get too close to it and then leave, when you come back, the councilor is gone, Bynryn is dead, and all but the one praying soldier have left. Also, when you start those quests, the fire gets worse in several areas over time and will kill Bynren and put smoke on the councilor's escape route if you wait too long.
That's the worst example, but there are others. Some scenes will wait forever for you; some will not. For example, if you want the cinematic of Arka grieving over Kanon, you don't have much time at all to see it.
