Implementing this in a non-invasive manner requires changes to the way Anki syncs cards, and the way cards are reviewed (eg a card may be awaiting review, then no longer pending after changes have been synced). Updates to the sync protocol were a small step towards this, but I’m afraid the rest of the work has not bubbled up to the top of the priority list yet, as bugfixes and other lower-hanging fruit tends to take precedence.