The "Immortality" game mechanic used to be an end-all, be-all status. There was nothing that could be done about it whatsoever. (In fact, the reason I started carrying SoG were those pesky Immortals and Phase Dragons.) That only one element had access to the creature status (even Anubis needed light blue) made Aether as a color OP enough to hamper further card creation for it. Earth, which is very powerful when compared to certain elements, is so because it offers both the measure and countermeasure rainbow staples concerning destruction, Protect Artifact and Pulverizer.
I am very grateful for the changes made to immortality in creatures in this game, i.e. letting shields affect them. I could debate why some shields make more or less sense for their abilities to hamper an immortal creature, but that is unimportant. For now, there is actually soemthing that can be done about it. Somewhat.
I would be in favor of a card which strips all "Immortal" status from the field when cast, for both parties, with whatever cost/color appropriate. Make it a new Miracle, if you want...but it should include all of those protected permanents, as well; right now, the only things that are completely untargetable/unable to be dealt with are those items which your opponent has rendered inaccessible. This would also neatly address the creature status of immortality, making it possible to become mortal
Granted, to balance this out might be hellish; destructive cards/effects of all types might have to be harder to pull off/more expensive to play. But I think in the end it would be worth the inclusion of a card that might make some situations less futile.