The idea of disabling permanents has been thrown around the forums in various places (as an additional effect to buff Air's Thunderstorm | Lightning Storm, for example), and a defensive effect like this thematically fits in with an Aether Elemental's set of skills.
However, I'm not too sure if relating it to the Phase Spider is the best way to go, as Death also has the Flesh Spider for creating tangling webs. Perhaps it might be a little bit more thematically appropriate if the card was something on lines of an Electromagnetic Pulse/Wave? Aether Elementals do control over electricity and energy waves, and can probably harness that energy to disrupt their opponent's permanents.
As for which permanents are affected by the effect, I wouldn't disable Pillars/Towers/Pendulums from working, as it would be too crippling a lock to recover from in the early game, especially if the spell's casting cost remains at a relatively low (and castable in the first few turns, and also very chainable) 3|2
. I would, however, let it partially disable shields and weapons by allowing only the damage dealing and damage blocking effects to occur, thus suppressing their "magical power" and rendering them as normal shields and weapons for the turn. For example, Permafrost Shield would only reduce damage taken from each physical source by 2 while Snared.
