Watch the original episodes, he is very much like a trickster monkey. Then he matured into what people remember him as and became very different, but he didn't start that way.
The original Wukong [1] flies on a "golden cloud" (does that rings a bell?) and uses as a weapon a growing stick (Ruyi Jingu Bang, transliterated in Japanese as Nyoi Bo, the name used in the Dragon ball anime and manga) that obeys to voice commands
In Dragon ball the golden headband (that can shrink as a form of punishment) is missing, replaced by a regular red headband that sometimes Goku wears
EDIT: of course I forgot the most important one: Goku can become a monkey. Wukong is a monkey, the monkey king.
In Journey to the west Sun Wukong learns to behave and start following a path of spiritual growth and wisdom that, at the end of his journey, leads him to become enlightened and a Buddha himself.
Much like Goku in Dragon ball, where trough the training and by following his master's teachings, he becomes a warrior with a noble heart that values friendship over everything else.
After that, I agree, it's simply about becoming stronger and stronger.
I didn't watch the episodes, I read the 16th century book Monkey, translated into English by Arthur Waley. Supposed to be a pretty faithful translation, which is why I was surprised by your comparison of Sun Wukong and Son Goku.
