From the demos, the max number of spell fire 'modes' is at least three. The fire spell had the "close range/self" mode of flamethrower, the "Ranged vs Enemy" version of a straightforward ranged fireball, and we were told it will have a "Ranged vs. Environment" version of a fire glyph trap.
I think what might end up happening for the bound weapons, lets say "Bound Sword" for now, is that the "close range/self" will bound a weapon to you, the "Ranged vs Enemy" will launch a summoned sword at an enemy, and the "Ranged vs. Environment" will be something like making a spike trap of blades or something.
Man, I really hope they do something like that, the spell would be versatile and sweet.
Now all I can think about is the different possibilities of fire 'modes' for spells. What does everyone hope to see?