I've made whole wheat chocolate chip cookies from Good to the Grain many times with King Arthur Flour's whole wheat flour and they come out great.  http://food52.com/blog/9497-kim-boyce-s-whole-wheat-chocolate-chip-cookies    When I mill hard red wheat and use it in the cookies (from finely milled to coarse) I get flat, barely edible cookies.    Anyone know why this happens and how I can fix it?   Edited to add: With the King Author wheat flour I use a 3T cookie scoop and the cookies flatten slightly and then raise. They have a slight crunch to them.  Using the milled flour and the same cookie scoop they at least double in diameter, do not raise much, and are very flat.  They are really hard to bite and can only be eaten when dunked in milk.  I wish I had pictures, but the times I tried making them I didn't think to take any. 
My suggestion would be to just go with the sugar increase, it might be sufficient to increase moisture. You can combine it with less baking time, if you want to - try using a thermometer and bake to 94 C, maybe 96 if it gets out underbaked.   If it still feels dry, you should add fat, not water. Increase the butter, and maybe add one more yolk.   You can also use an artificial sweetener instead of sugar, but it will again increase your dryness problem. An interesting option would be to use another form of sugar - replace part of the original sugar with some molasses or a syrup (corn syrup, agave syrup, whatever you find). It will make a moister, heavier cake, but also change the flavor profile.   I must also say that people rarely find pound cake to not be moist enough. If you don't like it that way, you might be the kind of person who likes cakes extra moist, so it might be worth looking into cakes soaked in syrup after baking. You will find most recipes for that from Middle Eastern sources. If that's what you like, you might want to try syruping this one too, it will solve both your moisture and your sweetness problems.  