Sleeping should cause mobs to spawn as if you waited out the night

If you go to sleep right at dusk, little to no mobs will be able to spawn before it becomes day. This is a major difference from waiting out the night (e.g. by mining or AFK), which allows mobs to spawn normally and linger around at daytime.

Beds are quite powerful (and possibly overpowered) in several ways; they skip the night immediately (preventing mobs from spawning), reset your spawnpoint and clear the weather. To make them slightly less overpowered, going to sleep should cause several mobs to immediately spawn in areas with block light 8 or lower (ignoring sky light). The mobs would spawn between 24 and 64 blocks away from you, so mobs won't suddenly appear next to you or in lit up places where they can't normally spawn.

This way sleeping won't completely remove the threat of mobs, but you can still skip the night like before.