Randomized teams wave spawn event is completely different game.
Usually it's 1 battle per hour which includes 30 minutes of waiting. It might not happen at all, and when it happens, you might not even make a shot before dying. It's a hard strategy / psychology game if fight is organized. Such conditions are leading to critical need of use the most effective even if boring tactics: camping, etc.
You don't care if you die in wave spawn insta action. So you just play. Even if weapon you get is always worse than enemies have, you don't care that much.
It's like public server in CoD compared to competitive. But competitive currently has pretty bad condition setup.
I really believe that such events being constantly runned can make the Fallout much more popular. Doesn't matter that it's only 20 people on the server, you always get the fight.