Excited to see how this one progresses, and keen to see you bend unity's tilemap system to your will. This genre of game may end up being "system-heavy", meaning that you spend a long time on making the game function (turn based, building placement, unit movement etc) and there is always the danger that the system devleopment takes up so much time that there is little time to "find the fun", so please be wary of this.
Overall the document was mostly well-written and gets across the idea nicely. Needed more detail in places and just a few minor grammar issues here and there.