MySQL is used for such a large number of business applications. A connector would really help with querying business data and generating alerts, workflow etc. To not have this connector will make this process much more complex.
MySQL is such a common database, including this connector and some basic triggers should have already been part of Flow. I have a front-end built on the Joomla CMS which writes to MySQL. I need to be able to use it within Flow.
You can now read and write data in MySQL databases that are on-premises. You can read more here: https://flow.microsoft.com/blog/button-updates-seven-connectors/