I had this idea, that instead of generating a password reset token and emailing it to the user, I simply email the user's hashed password to them. Then upon reset, the user would submit the old hashed password and the new password in plain text. The server would compare the submitted hashed password and the stored hashed password, and if they match, reset.
This could have some benefits including no expiration time on the reset email and no need to store/expire reset tokens.
What sort of negative security implications would this have?