Hi, really appreciate the feedback!
Understood, we believe we can halve the development time if we compromise either by simplifying the art significantly, or hiring a bigger art team so that they can work concurrently on different routes (though there may be differences in style. Perhaps each artist can take 1 route).
Another commenter had a good idea to start with simple BGs first (maybe line art for example) for release, and progressively, they could get more and more detailed.
On our part, we want the game to be out sooner rather than later too! So, thank you for sharing. And we will definitely tweak the timeline.