Whilst implementing SSO in an environment where Single Sign-on is used seamlessly we realised that the only option for logout was using the WSFED method due to PPO not having a logout page or url. Although this is functional it resulted in our team not being able to implement the ideal solution where, when logging out of PPO the user is not presented with a page where they are able to re-enter their credentials in order to log back into the instance - instead with the current functionality available you are redirected to a page with a message informing that you have been logged out. The user then has to re-run the PPO url to get to the login page where they can then login again.
I believe introducing the functionality to better handle the logout process for environments using SSO seamlessly will greatly enrich the user experience.