The strength of the parent image, I think, is that parents at their best are a combination of authority and deep love, which is a combination of features found in God. God created us, is much more powerful than we are, and is our guide and teacher -- so, authority. But God also loves us, loves us even more deeply than we love our own children. And the picture of God putting up with us, even when we're behaving badly, the way we continue to care for our toddlers even when they're throwing temper tantrums, is a good one.
The weakness of the image is that parents are flawed people, and parenting doesn't always go well. I had a difficult relationship with my parents. The language in the Reddit article of living "in constant fear of God's wrath every time we fail to live up to the perfect standard that Jesus showed us in His life" pretty well summarizes what the God-as-my-parent metaphor means to me personally, even though I think you meant the exact opposite in your article. So I don't use parental titles for God in my private prayers, and it's even a little difficult to address a priest as "Father" or "Mother". This is just me, though; I know that the parental imagery is helpful for many people.
One of my inferences from the gospels is that Joseph must've been an amazingly patient and loving father to the child Jesus, for Jesus to have chosen "Father" -- out of all the possible metaphors he could have chosen -- as his preferred title for God.