I have 2 regeneration feature ideas and 2 ood feature ideas. My first regeneration idea is that if you hold your  regeneration for too long and then let it go inside the tardis - the tardis will start blowing up with fire and  you only got 3 min to save it,  otherwise it will be fully destroyed and will only come back in 2 hours . My second regeneration idea is that if you start to regenerate you can use the hand in jar to stop the regeneration. My first ood idea is an ood planet that will have caves with oods sitting in them and also an ood city. My second ood idea is that you can have an ood slave that will give you food and all other thigs; if you treat your ood slave badly the ood will become a red eye ood and will start to kill everyone. I hope you like my ideas.