Why is faith so much more important than being a good person? I recently had a debate with one of my friends in which he asked "Why would a good and just God not make salvation dependent on ethics, but rather on gullibility, as the Christian God has?" and I couldn't provide him with an honestly good answer, and in fact it's a question that I need an answer to as well.

In Christian teaching we are taught that 'man is saved through faith and grace' and while there are scriptures that put emphasis on morality and service, that aspect seems to downplayed, and in fact there are some denominations in which you can be saved wholly by faith. What I'm getting at is that Morality seems to play a Robin to Faiths Batman.

Is morality really important in Christianity?
Who says that faith plays a more important role? As James 2:26 reminds us, "faith without works is dead." 

Faith plays a greater role than works in salvation (at the point of "getting saved") simply because none of our works were good enough before God to earn us righteousness. So by faith alone we are saved when we trust Jesus for righteousness. 

Then works start to play a significant role as they line up with one's profession of faith. Without works, our faith will be a mere intellectual practice; but God is a God of love and wants to express Himself through those who profess faith in Him, "Beloved, let us love one another, for love is on God; and everyone who loves is born of God and knows God" (1 John 4:7). And so the epistles (and Jesus) encourage good works. 

In the end, at the judgment seat, we will be rewarded according to our works (Matthew 25:14-30, the Parable of the Talents). Those works will be an expression of our heart and faith life.