Slight Problem with Anivia+Kalista

I was playing team builder, when I came across a slight hiccup. Said hiccup was the Anivia sup paired with a kalista adc. The problem is that, when anivia is oathsworn and in egg form (after "1st death") kalista can just pop ult and throw her under tower providing anivia protection that she, frankly doesn't need when paired with ridiculous AP ratios and hardcore CC. Now, I do have grounds to show that this should be changed, based on the fact that when zac or aatrox are using passive to survive, kalista cannot ult them, so why should anivia be the exception? I would dare say she should be immobile (immune to pulls that take her out of position, sorry thresh and blitz players) but I also propose that kalista no longer be allowed to pick up anivias egg and throw her like a ragdoll back to tower when she overextends and gets blown up (as if that would happen to any compentent anivia anyways).

TL;DR VERSION: KALISTA SHOULDNT BE ALLOWED TO ULT ANIVIA WHE SHE'S IN EGG FORM.