Separating light level from mob spawn and light blocks protecting further

• What?

Making mobs spawn with a different light level, instead of the regular light level.

• How?

This "mob spawn level" would consists of the block's light level + 4 extended blocks in range, leaving the light level of a block intact, and increasing the radius so it prevents mob spawn further. This radius is invisible.

For example a beacon will have a light level of 15, and 4 more  blocks in which mobs won't spawn.

Another example is the enchanting table, with a light level of 12 and 16 blocks of mob spawn level

• Why?

Caving in minecraft is painful, specially when you want to mob proof every single cave in a 128 block radius, this change will make this task more efficient, and thus less time wasted.

It can also help to build structures without being forced to place unwanted light blocks