Baking – Solutions of making cookies less crumbly and dough not being able to be shaped into balls

Well, looking at the recipe...

The sugar (brown sugar + honey) level looks roughly appropriate compared to the flour so that's unlikely.

The fat level looks a tad low for the cookies I normally do, but I've never used oil in cookies before. You might try increasing the oil just a bit to lend extra tenderness, but I don't think this is the real issue. (Using oil in cookies also means you're not creaming, which is typically important in most cookies...so its a bit odd, but I don't know that it would cause them to be 'crumbly'.)

The lack of the egg definitely isn't helping it to keep structural support. The recipe is basically banking on the fact that it needs to be moist to hold together. There's not really enough liquid to form gluten to add structure (which you don't usually want for cookies anyway). Since there's nothing in the cookie to give it 'structure', if you dry it out its just going to fall apart on you.

I suspect your problem is from the directions of 'Don’t overbake these, or they’ll dry out a little.' They dried out a bit too much and lost all support. It's easy to over bake cookies and this is a recipe with very little room for error in that area.

Citrus zest is where most citrus flavour in a sauce or baked good actually comes from because it remains in solid form, like herbs and spices. The juice adds some flavour but it turns into solution and gets spread out over a very large surface area/volume.

I don't know why you decided not to use the zest - are you using commercial orange juice? If so, that may be part of the problem too - processed juices are not going to be as flavourful as homemade, in part because of the mechanical separation of pulp (even if it is subsequently re-incorporated to make a juice "with pulp").

Orange juice is effectively your water in this recipe so doubling it means you need to double everything else. In other words you'll have exactly the same ratios and therefore exactly the same taste.

If it came out too dry then that means you either (a) baked too long, (b) overworked the batter, (c) didn't use enough oil or (d) didn't use enough sugar. Nothing to do with the OJ content.

If you really want to add more orange flavour beyond what the original recipe would give you, use orange extract, it's a highly concentrated orange flavour and is usually derived from (surprise!) the zest, or made to taste like one. But I would suggest to try following the recipe correctly before doing this.