I don't know how many of you are familiar with the Game Vanguard Saga of Heroes.
But in their game, certain creatures wouldn't appear unless it was a specific time of the day.
In Xsyon this could be Bats not showing until it is night, owls too.
Wolfes only appear to hunt at dusk or dawn.
It would make the world a lot more 'real life' and dynamic.
I think it would be cool, as it would force people to login at different hours to collect the different things, just as it would in our own world.