wicket-annotations is indeed not the best name to explain its purpose but this project is one of the most used WicketStuff projects and we cannot fix this without annoying its users.

wicket-annotations is not split in core, impl1, impl2 but isn't it possible to depend on the big/fat module for the needs of wicket-mount-runtime ?

Do it as you find the best.
Just add a comment when you are ready with any final improvements and I will merge this PR.