Spirituality != religious. i would not want the whole religion system tied into the spiritual trait.
Spiritualist Ethos very clearly implies some form of religion (perhaps something closer to an idealized version of Buddhism, though), given the government titles and descriptions. However, it's hard to see what a Universal Religion would look like in a universe full of sentient birds and fungi, and it would be certainly difficult to integrate religions with ethics as they are. The whole point of religion in CK2, aside from historical flavor, is that they tie together multiple states into a loose network and system of interactions. It doesn't make a lot of sense for a human missionary in 2400 to go around spreading the gospel among the heathen mushrooms of Zebulon V, who literally reincarnate every birth cycle
- 2