Q: I guess what I want to know is whether or not this is just another shooter (only with more players than normal) or if the world is going to be dynamic and filled with all sorts of different things to do.
A: The thumper mission is an example of a dynamic mission that happens in the world. Crystite is a very valuable resource. You use it to upgrade your equipment, your army technology tree, and it's a base form of currency in Firefall. You may just be walking through the world one day and stumble upon a Crystite deposit or you might be given a mission to go find one. You'll probably want to do it in order to advance some part of your progression.
The world is full of dynamic events. The attack on Dredge that we showed at PAX was another dynamic event. Normally, Dredge is not under attack. It's a perfectly peaceful town, but due to it's location and the valuable resources that are mined there, the town can come under attack by the Chosen.
Everyone in the area is notified of the attack and it's up to them to defend the town or lose it. If the town is lost, it will have to be regained before the city is usable again. This means that any missions, the forge, the dropship pad, etc are all gone until you, as players, fight to take the city back.
Other missions are based on time of day, time of week, time of year, or even player actions. We are trying very hard to make the open-world feel like a living and breathing place where things happen and you have the chance to make a difference.
These dynamic missions are on top of the story missions that will be part of the co-op campaign. There should be plenty for you to experience and enjoy. And all of that doesn't even include the competitive multiplayer which we haven't released details on yet.
Hope that answers your question.