He he he. I'll need projectiles first. That's going to be a dangerous spell... think about, say, an iron construct. If the barrier is made of several floating spinning blades, and the construct just leapt into it, the blades would bounce off and go flying everywhere. It would be like a grenade. One of the blades could get stuck in the ground, so it stops spinning (but the spell is still trying to make it spin), so if somebody goes to pick it up, it'll start spinning and rip into their hand, unless they hold on tight -- it might make a good thrown weapon, since it is instructed to spin really fast and float. Iron constructs are just going to be fundamentally hard to kill in this game, unless you're creative. Maybe a wizard could create one, and task it to hunt the player mercilessly (maybe cast a spell on it so that it always knows the player's location).
A blade barrier would also be dangerous if the player creates one surrounding his or herself, and forgets to make it move properly while he or she is walking. The same goes for "fire aura" spells and fire resistance.
Anyway, I fixed all of the basic problems with item models. I have two things left to do:
1) Don't print missing limbs
2) Liquid display
I'll either release today or tomorrow. There might be some annoying difficulties with both of these things, so don't count on today