Instead of a neutral flag that is brought to the enemy base, make a central specific spot, that when the player is standing in, it will gradually convert the flag to their team color, something like 10% conversion every two seconds or something. A visual flag color change would be helpful too, gradually changing the flag color from blue to red and vice versa. Kind of similar to RegenCapture mode in Sauerbraten. Both bases will have access to the area to convert the flag, and once converted, it can be brought to the appropriate base to score a point. However, if captured by the enemy team, it first must be converted to the appropriate team color.