Why are you offering Gaea 3.0 for pre-order while Gaea 2.0 still has unfinished roadmap items?

Because Gaea 2.0 and Gaea 3.0 are not being developed as a single linear effort. Gaea 2.0 remains the primary shipping target and will continue to receive regular updates until the roadmap is completed. In parallel, a small research track has started early work on Gaea 3.0 now that the major research work for Gaea 2.0 is complete.