strange spawning mechanics

Minecraft is one of the only 3D abstract based graphic games that can boast having top tier immersion. But nothing ruins your minecraft experience than a pig spawning straight in front of you out of thin air. Whether its a zombie or zombies spawning out of nowhere, or a piglin popping out in your clear line of sight in the nether, the fact remains the same; the abrupte impossible appearing, will damage your experience. 

This is why mobs should only spawn outside of the players vision, no matter what. The mobs should also spawn one at a time. Mobs sometimes spawn in trios or duos on the same spot, like zombies at night which can be annoying and can be easily spotted. 

So please consider this suggestion which could ultimately improve gameplay greatly.