I've been thinking about this, and there is a pretty simple solution that would cut down development time by a lot:
Scrap the Vault.
It's one of the worst coded, buggiest sections of the game that probably takes up the majority time of both dev and testing, and yet it's not even a primary feature. No matter how much time they spend on it, there is always a scene that doesn't unlock, a back button missing on a page, or an entry that plays the wrong thing. It clearly wasn't built to be scalable or in a way that's easy to add new things to it, and worst of all it's not even a good implementation of the feature they are trying to make. It doesn't replay scenes, it just shows the static art sans dialog, and the majority of the vault content can be seen in a more complete form already with a minimal amount of effort on the player's part since most are from repeatable content.
So what do you do? Leave the code as it is to prevent more bugs, hide the button to access the area and forget any of it ever happened. And when you get some free dev cycles, work on a new system from the ground up that is actually designed properly, one that is meant to accept new entries and maybe one that doesn't need to have everything created manually. Once that works as intended, then you worry about adding it back in.
Continuing to sink more effort into a thoroughly broken system that doesn't even meet the feature requirements expected by the users is just a waste of everyone's time.
