Yeah, i've got to agree...while the randomness can be annoying i know for me at least it gives a tremendous amount of replayability to the game.
ALTHOUGH just thinking about it i would add in one caveat. When it comes to sets...the game should be built in a way that if one piece of a set is found in the gameworld then that should guarantee that the others are out there somewhere.
It almost makes sets irrelevant...i think ONE time in KBTL i made the ogre set...and that was after many, many, MANY replays.
cheers,
DW