Hi Gerry,
Thank you for sharing your ideas with us.
Just to let you know that since OutSystems 9, the usage of MySQL as database for the platform is supported. Also, using OutSystems Database Integration API SDK there is already a database plugin developed to support integrations with this database as you can see here.
Currently we are not having enough demand from the enterprise market to support Postgres as the database where OutSystems platform should run on top. Therefore, from the moment that part of the idea is not on our radar to be implemented in the near future.
Cheers