I'm thinking that hiding under desks should be useless against the Fiend. That may sound overpowered, but it's really only logical for the Fiend. Having it miss the player hding obviously under a table really makes it look rather pathetic :P
It should also be a little more systematic with searching through hiding spots, e.g opening both lockers in a set/ opening shower curtains in a row, and it should also have a higher chance of finding the player. Right now, it seems to find the player less often than the Hunter for some odd reason. Â This could punish the player for hiding.
Lastly, I think the monsters should eventually instant kill the player if they find them in a hiding space. Maybe the first few times they find the player, it throws them aside as usual, but eventually, they just resort to killing instantly. This would make hiding much less of a safe-point, and allow there to be an actual threat of being found.
I don't know, just me rambling again. :P