No, Theon is the most annoying teen rage in the series. Joffrey is far more complex than him

I don't know how you got to that.
Joffrey's a simple kind of monster. He was raised without a father figure because Robert never cared for him, and his real father, Jaime, had to be a distant uncle or forsake the truth about he and Cersei. Speaking of Cersei... she's the entire reason Joffrey svcked. She was absolutely crazy, and she was obsessed with being like her devious father. So by trying to be that, and instilling those values on her son, she created a misguided monster.
Joffrey had no talent to speak of aside from being good-looking. He was a little [censored], a bad king, a horrible person who had Sansa beat because he was afraid of her family challenging his rule. There's nothing complex in this, this is just being a [censored].
Meanwhile, Theon is incredibly complex. He was born the third son of a hard father, who rebelled and lost both his elder sons. Ned took Theon hostage as his 'ward' to prevent another rebellion. In the North, Theon was a prisoner who was raised a northman, and that troubled him. He would constantly try and act like he was alright with it, taking on Ned's son as a younger brother and trying to act like he was superior than Jon and the like.
When he went with Robb to war, he got some freedom and was sent to the Iron Islands, where he thought he'd be missed, but then he saw his own people had scorned him, especially his father. Desperate to gain the respect of his countrymen and his father, he took over Winterfell with only 30 men, and ended up losing it to the madmen of the Boltons.
His story from then til now is really quite sad. The amount of fear he has for Ramsay proves that the bastard did some REALLY messed up things to him. If you've read the excerpt chapter from Winds of Winter, Stannis calls him the "Bastard of Bolton" and he freaks out, warning Stannis never to call him that. Why would Stannis care what he calls his enemy in his own camp? Another example of how much fear is a part of Theon.
My favorite chapter in DWD was **DWD spoilers** When Theon was in the ruins of Winterfell and had the nostalgia-blast of his childhood and started filling with regret. The best line in the entire book, possibly the only one that gave me goosebumps, was when he thought of Robb and wished that he would have died with him. **spoilers**
Joffrey svcks. Theon's awesome.