The day and night cycle doesn't really matter (my opinion). If you feel it is necessary then its your opinion, but for me no game will get worse the moment you remove it. After all, it's cosmetics anyway, unless it's not then that it can be annoying.
That is one of the reasons I am not a big fan of the day/night cycle. I actually like it more if it is just cosmetic. It's cool, but not necessary.
But stuff like... "Come back at night so you can do X" or "Character Y only comes out at night, come back and search for them!" is more annoying than it is entertaining or fun... nor do I really think it adds to the immersion of the world.
