I purchased the software and, overall, I'm happy with it. One improvement I'd really like to see is sharper pixel rendering, especially when working with pixel art. It would also be great if the maximum zoom level could be increased to allow for more precise editing.
A dream feature would be direct export to the Amiga *.IFF format.
I really hope the project continues to be actively developed, as it has a lot of potential.
For inspiration, you might also want to take a look at the free tool Unfaker, which includes some useful features that could complement your application: