I’m a big fan of modding and game editors. people love to tweak a game they way they want it, and I support that 100%. So with this in mind, here is a work-in-progress screenshot of the custom scenario editor.
The idea is that there is a new way to launch a challenge (maybe from the challenges window), rather than selecting an existing singelplayer mission. That new button takes you to this screen which lets you tweak everything. Once done, you can then click deploy, and arrange your fleet like any other mission, then issue that as a challenge to anyone else. You can only use backgrounds that already exist in the game, but everything else is tweakable. The only big chunk not done yet is changing the deployment zones. I may end up adding that later and using defaults for now. My UI coding is sadly slow and inefficient :(
Together with in-game messaging, this is the second big feature that will be in the next patch (alongside many bug fixes) which will be 1.28