Fair points here.
I completely disagree that seize is more orderly than slaughter. Even as a melee I found great ways to contribute in Slaughter and I always knew where to go, and my entire alliance was almost always with me even with completely randoms in queue. In seize everyone just runs where ever they want. I believe that the best success will be gained by each party of 8 sticking together where ever they need to go, but right now no one listens and does their own thing. In slaughter it was easy - go to the middle. In secure it was an understood meta that solidified quickly, and was easy to pick up by new players. In seize, there's no direction, and no leader, and if someone tries to be a leader, since it's random internetz you'll typically get trolled on or told to shut up. And it's precisely the RNGness of seize why a "meta" like "A goes left, B goes middle, C goes right" will never develop, and any semblance of a meta that might develop will be variable and not as easy to understand or spread to newer players. It's not the lack of order in the map mechanics that bugs me per se, it's the lack of order between the random 24 teammates. The other maps' gameplay helped guide players into where they should be in a way that naturally corralled players into stick with their 8 person party. Seize does not do this.
I'll keep trying to tell my teammates to stick together but right now it falls on deaf ears. Like I said in Secure or Slaughter, chances were good that at any moment I am in close quarters with my healer(s). In seize, unless I make a point to follow them, my HP pool is entirely my job to maintain. Not very good in the only PvP map that actually punishes your team's score directly for dying, which means your teams' progress towards winning is lessened when you die. That makes healing and staying alive more important in Seize than it is for Secure/Slaughter (ie. if you die in Seize, BOTH opposing team's scores changed relative to yours, whereas if you die in Secure/Slaughter only the opposing team who scored the kill will have their score changed relative to yours). So in the map that makes it more important than ever to travel in a tight team to keep each other alive, the mechanics and RNG nature make everyone spread and thin and vulnerable.
Let's not discount though that nodes are much easier to defend once capped than they are to take. So if we assume an average of equal cooperation among the 3 teams, a "lucky spawn" for one particular team immediately gives them an advantage because 1) They will cap it first and get some initial points out of it and 2) The opposition has to send MORE offense than you have there for defense and basically wipe out all defenders before they can take the node AND they have to cap it TWICE to start getting points out of it. RNG is RNG as you mentioned in your first post and there will be games where RNG is the deciding factor in your loss just like it will be the deciding factor in some of your wins, but sometimes you can "respond and react to those specific situations" in the best way possible but you'll still come up behind because of the RNG factor. That will never stop being annoying.
Like I said I like random, it's healthy for games. I guess my complaint isn't so much with Seize as it is with my 23 random teammates who behave randomly on a random map that are about as easy to herd as cats. It makes my contribution feel like next to nothing. I really think they should stick to 8v8v8 for Frontlines, or maybe 12v12v12 (three light parties of 4). I was always happier when a secure/slaughter queue popped as an 8v8v8.