The strategy is a little different for each map, you obviously want to control 2/3's of the map and keep the opponent back in their spawn..... however, with Shores of Time this is a little different because of how easily B and C can be defended from afar. The reason you don't ever want to cap A on Shores of time is because that side of the map is at a disadvantage due to asymmetries in the map. Notice how the line segments AC and AB are much longer than the line segment BC? That's the disadvantage the A flag has when it comes to controlling 2/3's of the map. You also have a nearly perfect line of sight to both B and C, which makes it much easier to team shot enemies that are trying to rush in. The three ways that the enemy team from A can push B or C requires them to come through much more narrow lanes, or "chokepoints". Add on that from B you are shooting down on your opponents and they have to shoot up at you. Another advantage. The best way to flank from A is to come up through the caves, but since that is near their spawn and since they all have a very easy line of sight to C, you have to push up with teammates. So flanking the team that has B and C takes coordination from a team due to how the map is set up. OP makes a valid point, you generally want to stay away from capping A on this map...