I think they should replace the enemy forces mechanic with a bar with checkpoints. Kill X amount to hit the first checkpoint, this is all that’s needed to complete the dungeon for vault credit. Hit the next bar, get one item in the chest at the end. Another at the next bar. For a full clear killing all trash (or some reasonable amount in more open-ended dungeons) hit the last bar and get either another item in the chest, or if that’s too many items a gold reward and/or augment runes for everyone.
That way tanks don’t have to memorize specific routes and a group can choose between a stealthy fast clear for vaults or a full clear for max rewards. If a run isn’t going well you could choose to change your plan mid-run instead of abandoning it and just finishing for credit instead.