I suggested this in chat, maybe it'll get some more support here, or less support :P

Maybe phase dragon should phase in and out of immaterial every other turn. So first turn it's immaterial, then 2nd turn it's targettable, 3rd turn its immaterial again. It gives us a chance to destroy it, although they COULD parallel universe it (although if they PU it when it's in material phase, it stays in material phase and doesn't phase back to immaterial).

Just a suggestion. Don't really like this new immortal dragon, why doesn't any other dragon have an effect lol

EDIT: Btw, the phase dragon was always the problem of aether, it was never PU. If aether didn't have something to PU as strong as phase dragon, it wouldn't be OP as it was and wouldn't have led to nerfing of 3 aether cards lol.