Not exactly. Zuko was not a truly evil character - he had a good side. If he was evil, not to mention that he admitted himself to have been so in The Western Air Temple and Katara referred to him of having a lifetime of evil shortly afterwards, it was solely because he was trying to capture the Avatar at all costs and was ready to kill the Avatar if necessary. In fact, it was because Zuko was caring and kindly that he ever found himself in the situation of wanting to capture the Avatar. Zuko's kind heart led to his vouching for an entire division of Fire Nation soldiers against Bujing's plan to betray and sacrifice them in a diversion - an action which led to his banishment, until he had captured the Avatar.

In his quest to capture Aang, Zuko attacked the Southern Water Tribe, manhandled an old woman (Kanna), burned down Kyoshi Island, and pushed down an innocent man (the Senlin Village leader). Indeed, he was unhesistantly prepared to save the life of his enemy Zhao, showing that his animosity was all for Aang and anyone who was getting in his way.