In general the capture/defend zones on points across all maps are quite small. Whats more is that on certain cap zones (Example, Last cap/defend point on Refinery) that are buildings, only one floor of the two stories is counted as the zone. That's pretty odd.
This is especially bad for co-op mode because the AI are just funneled up stairs and through doors making it very easy for players to just sit and hold a point. If the cap/defend zones were expanded to the top floor, bottom floor or outside to the perimeter wall if an area had one would make defending and capturing points far more enjoyable and challenging.
It's just far to easy to clear points with explosives due to the confined small space of the zone.