It's amazing to see that even in 2015, our hobbyist computer still receives so many new developments. These efforts are no doubt highly appreciated by everyone, but I think we can do even better. This post is being made to encourage everyone to start thinking, ironically, about future users, and future developers.
Sakura here, is leading the way:
Transparency. The benefits are clear: If you open your code (and designs, in Sakura's case) up, you allow more people to participate in it. You may grow tired of your project, but others may continue deriving benefit from it. Is what you really want for everyone to start again from scratch, to painstakingly reverse engineer what you've already achieved? Attribution doesn't go away with Git repositories, you know. :-)
I cannot imagine any reason in 2015, why most new Amiga (or retrocomputer generally) apps should not include source. Most likely you aren't making any money from this stuff. Why not allow newcomers and existing enthusiasts alike to learn from your work, and for existing users to continue improving it? As much as I'm speaking to individual app developers, I'm also looking at you Hyperion, A-EON, AmigaKit, Elbox, MorphOS team, etc. It isn't the 1990s anymore.
Again, much love and respect for your work. But let's make what's left of Amiga land all about educating and sharing, as much as it continues to be about impressing the living hell out of one another. :-)