The areas are capture points that, when captured, allow you to choose between 4 upgrades (1 weapon guaranteed) of a rarity defined by the colour of the capture circle. Weapons set the base stats and modifier upgrades upgades these and carries over if you switch weapon.
Did the bots move around and upgrade when you did the corner strategy? The corner strategy is supposed to be a losing strategy, since you are not getting any upgrades and will fall behind.