Based on what I've seen of the series, I don't think that Goku is a terrible parent. It's more like he's too much of a kid himself to be a more typical parent. He does care about his children and even his reaction to Pan disappearing in the previous Super episode was a bit more of emotional than I expected. I agree that he isn't going to win father of the year, but at the same time, I don't think he's quite as bad of a father as I've seen people make him out to be.
I wouldn't call Goku a bad parent because he cares deeply for his family he would go to the deepest ends to keep them safe, but at the same time he clearly isn't much of a family guy given how he cares more about fighting than actually being there for his family.
It's a mixed situation for me. It was the father-son angle that got me watching DBZ in the first place, only to notice Goku making a lot of absence time (nevertheless, it has to be noted that Goku has spent more time with Gohan- eight years- than any of his friends and allies). He does love his sons (pain over their being harmed or endangered), BUT his love of fighting is the greater priority and his manchild nature would make him ignorant or fickle to any realization that he may have hurt them ("I've neglected my kids!...Oh well!"). It's a pro to Gohan and Goten that they don't bear any bitterness to it.
I wouldn't say that Goku is a horrible parent, as he does really care for his kids. But, as everyone has pointed out, he just loves fighting so much that he tends to leave his family behind a lot and he doesn't seem to know how to handle really emotional situations due to his manchild nature.