Do you not think it's dark enough? I think computer settings play alot with that, as sometimes I think it's not dark enough and sometimes I'm like damn should of brought a torch. The moonlight in game does show I spose they could optimise it more

It does get more dangerous at night, higher tier mobs venture depending on boss you've killed in the world and wraiths are night time spawns for the swamp. Fenring are night only in mountain. Serpents are kinda night time spawns but i don't think it's impossible to see them during the day. Oh and Odin is night time only, aswell as Thor being storm only