As I said in my post, in a17 farming was OP. In a18 it is way under powered. And you are correct, investing points in farming yields very little gain compared to investing in other skills. Unfortunately I already invested my points in farming, so those points are gone.
If plots were larger (ie 2x2, or 4 squares, or 3x3 for 9 squares, or larger) it would make more sense and be feasible. As it is the investment in resources is fine, but the size of the plot for the investment in resources and points is not, especially in a single player game where you have to be a jack of all trades. Imho, all they have to do to fix farming is make plot size bigger.