some defensive positions are just immediatelly overrun by the enemy, because the defending team cannot get to them in the time,
so i suggest that at the beginning of the match, defenders are able to chose some defensive positions as their spawn points, only one squad can spawn there (in case it does not, the spawn point just dissapears, just like the control point spawn point), then the spawn disables.
also, the duration of the spawn point that forms at the beginning of the game / when point is lost in assault game mode, needs to be extended for about 10 seconds, and should not prevent building of allied rally points (just like the old spawn points should not, when they are still around even though point has been captured)