Please, please, please let this become a thing. I hate how many sites force you to jump through hoops to remove your data and/or close your account.
presumably a .delete domain wouldn't be "quick and easy", you'd still have to authenticate and perhaps verify intent via OOB method. however, the link to the action would be well known and obvious, instead of having to dig dig dig around a website.
Many services don't even allow you to delete your account, just to disable it and have it hang around in their database as long as they want. That's a blatant violation of privacy.