Lets say you regenerate and damage your TARDIS, its at 0 health. Make it so when this happens the interior will break/collapse and you need to repair the tardis for the interior to fix itself.

Another idea, make it so you can change the interior of the TARDIS

I like this idea!

as far as changing the interior I believe this will be a feature of Dalek Mod 1.16 when it’s (eventually) released :) 

They should make it so that when you change the interior (Or the interior changes due to regen), you have to exit your TARDIS and wait a minute or so for the interior to change.

The self repair thing should also be the same, but to repair the tardis interior. Also have an option to select randomly from unlocked interiors