We've got Anubis, which lets you fully de-immaterialize creatures so this shouldn't be too meta disruptive now.
Note that it only allows players to target their own immaterial creatures and permanents, but not the opponent's.
... So what about fractal phase golems and such? ... well you can do that already and nothing seems broken by it.
The sanctuary disruption is somewhat of an afterthought, but just being able to target your own immaterial cards seemed a little to situational to warrant an entire card. Any other ideas?
thematic reference:
http://en.wikipedia.org/wiki/Harmonic_Convergence
