Making it "Hardcore" as u say, would actually ruin the game mood... it's supposed to be scary... not a wannabe "GET TO DA CHOPPA!" action game -.-'
Please keep in mind that Amnesia is a game that is made of 3 things: Mood(85%), Realistic First person action(10%) and last but not least, Pure Awesomesauce(5%).
More flying books and more monsters would mean that it's not a scary haunted castle anymore, it would be some kind sick, twisted House of Doom-ish Apocalypse: "DODGE THE BOOKS! AW CRAP, I CAN'T MOVE! *insanity kicks in* oh snap, INCOMING! *Daniel Gets ripped to shreds by 15 Demon-Zombies*".
The way i see it, Left 4 Dead and Left 4 Dead 2 are the games you want my friend, not amnesia.