Wow, what a brilliant initiative!
Yes, as you say the camino has the religious aspect for those who seek it, however many who walk the camino do not do so for any religious reason whatsoever. It's not to say that we do not find it spiritual, but any long distance walk can have a spiritual element. In fact, that is often commented upon by people who do through hikes.
I'm not sure how they're going to achieve "always be on public land, exclusively pedestrianised and without Tarmac", (quote from another article on this project) but still keep it as a continuous walk. I guess they might include parts of the GR22 or GR50. Portugal is a wonderful Land with fantastic people, and an initiative that helps spread slow tourism across more regions and time spans is a good thing.
What is going to be extremely interesting is to see the infrastructure. In parts Portugal has good camping facilities for example but with the exception of the aforementioned camino trails and the Rota Vicentina, I'm not aware of too much infrastructure aimed at Walkers.
I look forward to reading more about this in due course
Hopefully some of our Portuguese forum members can enlighten us further!