DokB wrote:I never got to play live long enough to experience Fortresses.
What do they entail? Are they just zerg fests or is there room for roaming groups?
Fortress are mostly bigger keeps, you have the outer wall which is facing only one way (you can't cirlce/surround the outer keep like the ORvR ones), with two outer doors (also there are posterns if i recall correctly). So it's required a lot of people to funnel properly, especially if posterns follow the same keep mechanic.
Inner keep is bigger, you have two inner doors (plus postern) that are at 90 degrees apart from each other, also you have more ramps 3 (or four if I rememer correctly: two inner ramps and two outer). The lord is really a LORD, meaning that it really hurts (at least it should).
Side note: you have also more guards in and around the keep (that used to be champs).
Basically, the defenders have alway acces to the fortress during outer siege (they can't be ganked), and a stronger npc presence, however attackers have more ways in and more siege (although I am not shure about this part because of the many changes made since then).
To answer your last question we should know the fortress implementation in the current mechanic, I believe that roaming groups will have a smaller role, bringing the focus more towards WB vs WB. However, they could still gank the possible reinforcements once the outer doors are down.