Well if you notice though as each season goes on the aim of audience is split between children, teen and adult with jokes and references being made that certain ages would understand like in season four's Lost and Bound and the whole "Bewitched" reference. My 9 year old cousin doesn't get that but I watched the repeats as a kid and knew what they where on about. After season one they knew which ages where watching and where able to become a little more "grown up" with the content as a lot of parents didn't want small children watching it. So I don't think they goofed, I think season one was an experiment, they didn't want to cause a lot of bother and then season two on wards they became more "adventurous" with the effects and dialogue... seriously, the line "You don't need Dick" was aimed at adults in "Beware What You Witch For"
*hugs*
xoxoxo