a) Yes it does, it's programming.
b) Yes, it would.
I know how probability works, I'm not entirely sure you do. Besides, you're only talking about high end softcapped builds and even then it would still increase the difficulty. Do you honestly believe a Blaster could easily herd the entire map of a Magisterium Trial without breaking a sweat? Even Brutes on a fire farm with softcapped defense and capped resistance can succumb to RNG failure.
Also, I'm not sure it would necessarily result in people herding entire maps, especially if target caps remain the same. A team standing around doing nothing for 1 minute, let alone 20 sounds highly inefficient. It would be fun to test at least.