It'd be great to have all DCM connections available in the Data connections window.
And when Use Data connection Manager (DCM) is ticked, The screen defaults to DCM Connection list.
Yes it would be good to have the option to turn on the default in the User Settings.
This would be super useful!
You're right @Aguisande - overall our users are confused by DCM because the connections don't work in the same way as they do for other connection types - for example if you have a SQL connection then you need to use QuickConnect (which is not self-explanatory).
It feels like this is a great project for the UI / UX research team to see what makes the most sense to both new users and users who have been using Alteryx for a while.