The other night I made a derived version of pomegranate chicken and came up with a few questions.  The recipe I used was:   1/2 pomegranate (smashed)  1/4 cup of water 3/4 cup of powdered sugar 1 oz. salted caramel vodka 2 orange slices (smashed)   I let the mixture simmer and added it before cooking the chicken.  The questions that arose were:    Besides powdered sugar what other ingredients can be used to thicken a sauce? Is there a possible sour contrast that I could add to the mix (besides the pomegranate) to cut the edge of the sweet?  
Powdered sugar doesn't seem like a great thickener to me. It takes a lot to thicken a small amount of liquid, and as you've noticed, that means it'll end up pretty sweet. As an example, you can make a glaze (e.g. for cinnamon rolls) with a cup of powdered sugar and only a few tablespoons of liquid.  Generally, people thicken things using starch, most commonly flour and cornstarch, but also things like potato starch, arrowroot powder, tapioca/cassava starch. They're stronger thickeners, and don't really have much flavor of their own.  So I'd use as much sugar as you want to balance the pomegranate's sourness, and then use starch to thicken. You probably won't need extra sour at that point, but if you want it, you could certainly add something like lemon juice or vinegar. 