The source code is not ready, what's the point in publishing WIP ?
Because someone might look at it and say "Oh, that's a good idea - I can use that trick in my project", or "Oh, I see how you could solve that problem - here, try this."
Open source projects aren't museum pieces. People aren't supposed to look at your beautiful code artifact and gasp in awe - they're supposed to use your code, imperfect as it may be, as a springboard for their own projects, or to try something experimental, and if it works, contribute the result back to you.
For example, because the source code is available, I'm able to experiment with the Chameleon port of the Minimig core. I've already implemented a simple Akiko-style chunky-to-planar converter. The source for my changes is already public even though it's far from perfect. Is it compatible with a "real" Akiko? No. Is it useful? No - it's slower than a CPU-based C2P. Is it interesting? Hell yes - it demonstrates how to add new custom chip registers to the chipset, so someone might find it useful, and that's all that matters!
I'm currently reading, annotating and trying to make sense of the TG68K bridge, so I can have my Akiko running at ZorroII speeds instead of chipram speeds. That work will be released, too, as soon as I have it compiling cleanly and doing something.
The 68k is done (somebody on this forum already has it)
(Is that the core known as J68?)
Agnus is almost done. Then, I have to change Gary and maybe add a cache to the 68k.
Things take time, especially when you want to simulate the whole system.
Indeed - but in many ways a project like this is never "finished" - so release early, and release often