Can we fix Banner of Command?

Specifically, the Promote active.

Sure, the item isn't overpowered on the level of, say, the old Zhonya's Ring or the current Rageblade/Devourer combo. It's just a genuine pain to deal with when playing any sort of AP champion without a decent basic attack. Just seeing that blue sphere around a siege minion and knowing you're pretty much useless against it might just be the worst feeling in the game. After all, it's a minion that costs next to no resources to make.

I realize the magic immunity was to prevent it from being cleared instantly by the likes of Anivia, but surely there are other ways around this other than full magic immunity. Immunity to AoE damage would shut out a far lower percentage of the champion pool while still retaining the original goals of resistance to waveclear, and have the benefit of also being resistant against physical waveclear. 50% or even 75% magic damage resistance would be a hard nerf, but would make playing against the promoted minion a much more pleasant (relatively speaking) experience.