Hello, this is a request for a feature that is super-important.
Tri-planar projection allows for highly detailed terrains without the overhead of UV-unwrapping combined with large numbers of high-resolution images.
Only a few medium/low resolution, tile-able images are needed to get started for very large terrains since the image repeats and the scale of repetition can be controlled.
This technique projects the same image along all three axis and uses the model's surface normal to determine which rotation of the texture will be used for that section of the model. This allows for stretch-free texturing.
The technique is well-documented on various open-source websites. Below are a few links to get started with.
Thanks for your consideration - Marc Clint Dion.