Your comparison with Call of Duty is - sorry for my words - absolute bullshit!
Call of Duty is a game which is rated 18+. If younger children play this game this is not legal!
So if you use this as agumentation to change rules on World of Potter, you should start this change in politics!

On the rest I won't add any comments, cause Anni already did.

I do not really understand this rule change proposal...

1. It is possible to write about sensitive content in plays, but you really have to choose the correct X-rating for your play. If you chose 5X it is possible to write about death and violence if you do not write it in details! (an in fact you shold set a disclaimer as well!)
2. If you want to harm your playpartner in any way you always need his okay to do that, otherwise this would be powerplay/metagaming or godmoding.
3. You are talking about we should respect that we have got users who are 13 and you do not understand that. Well... have you ever heard about laws? Maybe the Youth Protection Act? Than you should defenately know why we have to respect the age of our youngest users! It is NOT only the rules made by World of Potter, but also the laws of the countries! And we all have to comply with these regulations.

So from me you get an absolute NO for this rule change proposal!