This as already been said, no doubt, but I'll say my two cents anyway.

I think that CS's should be skippable if you've already seen it once.

However, I do not think that players should be allowed to start the Dungeon until everyone is out of CS. It's too easy to exploit the system otherwise if they're allowed to act freely otherwise. That is to say, in addition to not being able to start the dungeon the timer on the dungeon wouldn't start.

Also, FFXI would allow you to see the CS before entering a BC for Storyline missions. If everyone who needed/wanted the CS, for example, came by a wee bit earlier than everyone else and saw it then they could enter the battlefield NP (upon touching the entrance again). Also, the people who do not need/want to see it could just as easily choose to skip it and then select to enter the dungeon when they click the entrance again.

I think that would solve the timer problems as well as the people who do not want to keep seeing the same CS over and over again. =D