Some item placements were changed, however I have yet to see what was taken out of the game.
One thing that was taken out was a holy sword. Well, you can still get a holy sword, but there isn't one just lying out anymore. In the PS1 version, there was a holy sword just lying there in a hidden room just above the room with the two pillars, but that was replaced with one of the new familiars. Now the only way to get a holy sword is as a drop from the Vandal Swords in the Clock Tower of the first castle.
The one problem I have with the PSP (DXC) version is that while there are two new familiars, they're pretty much the same as two of the original game. It's just that they have a slightly different appearance. If you ask me, they are pointless.