As much as camping the enemy GY in WSG might seem like a good strategy, it makes it incredibly hard for the camped team to make any sort of counterplay to either protect themselves or bounce back with objectives, and this feels incredibly counter-intuitive to why people join these games in the first place. It's not fun to lose that hopelessly and when it happens consistently in randoms people either stop queueing or just stop fighting back altogether, and then people wonder why no one wants to queue when they're constantly losing in certain BG's.
In some other BG's Blizz had the GY protected with a bubble that prevents the enemy from entering and doesn't allow you to cast spells. I think that if Blizz elevated the GY's above the base so that enemies couldn't drop down or target from below, with this on top, and prevented anyone from reentering, it would prevent the enemy team from camping the GY and it would prevent both teams from using the bubble to hide and evade the enemy team.