Dream Halls - I can see this, people will try to play it, but it most likely will be too slow.

Mox Diamond - Hmmm... It's a 0 casting cost artifact that can produce mana the turn it comes into play, yet it takes a land out of your hand (people know its errata'd right?).  I don't see this in multiples becoming too much of a problem. How many mana producing lands to people put in decks nowadays?

Grim Monolith - Mishra's Factory & Metal Worker are far more dangerous and unrestricted.  I'm not too sure what unrestriction would do though...

Fact or Fiction - Its also much too slow.  Would bring back some Mana Drain decks.

Library of Alexandria - Has anyone thought of unrestriction & errata (making it a legendary land?)

-JTM