Dragon Ball Z Is not perfect, and then again nothing is, but this is as close to perfect you will find in a anime. most anime has a problem i like to call anime sickness, anime sickness is when a arc or fight gets super dragged out, to the point where you wanna quit watching the show all together. Dragon Ball Z however does not have this issue, but they don't prevent this issue by making the arcs and fights shorter. they have transformations. just when a battle would seem to get dragged out the villain or the protagonist would undergo a transformation. This feature keeps story arcs and battles fresh.
Now this show is not lacking in character development either, the characters in the show are well written. and many get their time to shine. although the development in Goku's character is lacking. you will see characters like Vegeta and Gohan change drastically through out the show, unlike Goku. Goku pretty much stays the exact same through out the entire show, and i found the lack of change in his character disappointing.