I ship Zutara because Zuko is rather hot-headed and angry and confused in the right choices. Katara is kind and compassionate. While Zuko is confused, Katara could help him through these times and guide him to the correct path. They could genuinely care for each other and it would work rather well.
Also if they got married, future wars would cease! Uprisings and wars would be stopped because of the unity of the nations.
I think I might have over thought this. I really like Zutara and Taang. Taang is just really cute.