My main concern is this: with how much work Venus and Railjack updates are I worry how DE are going to find time to give us more Umbra frames until the next quest comes. And that's if we forget about adding regular frames (which need a quest or some kind of backstory nowadays), primes, new weapons and whatever other things that DE are working on, like possibly Melee 3.0 or Kingpin system.
With how Excal Umbra was introduced it means that other Umbras will probably need some kind of backstory, and considering that even recording voicelines can be difficult to arrange sometimes... I don't know. It's possible they'll just drop Umbra frames on us like they do with primes, but then the whole thing will be way less meaningful after all this talk of "relieving warframe's traumatic memories and taking away its pain" in the Sacrifice.
What do you think?