Aziraya would probably be red, for several reasons. The fact that the red lantern rings tend to corrupt the user's body/blood fits well with him. I roleplay Aziraya as lethargic and overall lazy, using the idea that his Warrior's rage dumps an absolute overdose of endorphins and adrenaline into his body. Over time of fighting like this, his body just can't muster very much energy/strength unless he's consciously flooding his system with these. Since this is how he fights, he essentially has near-constant control of the portions of his endocrine system that relates to energy. He actively makes his body store it for later release... meaning his body doesn't really get it in normal amounts during regular activity. The issue with being a red ring though is that the red ring is supposed to be uncontrolled, unbridled rage. Aziraya has a bit too much control over it to really fit well.
He was recently described as a hedonist, which isn't too far from the truth, so maybe orange? The problem with this though is that he isn't a hedonist in the "hoard all of the women, all of the wealth, all of the power" kind of way. He just... really appreciates the simple pleasures in life like a comfortable bed, looking at something visually appealing (whether it's a painting, a woman, or a large aethryte crystal), the taste of a good spiced wine as he relaxes, the soft feeling of a luxurious rug under his feet, a warm bath after a long day, etc. If he doesn't try to hoard it, it doesn't really fit with orange.
I guess he just doesn't feel strongly enough to truly be a wielder of a ring.
He was recently described as a hedonist, which isn't too far from the truth, so maybe orange? The problem with this though is that he isn't a hedonist in the "hoard all of the women, all of the wealth, all of the power" kind of way. He just... really appreciates the simple pleasures in life like a comfortable bed, looking at something visually appealing (whether it's a painting, a woman, or a large aethryte crystal), the taste of a good spiced wine as he relaxes, the soft feeling of a luxurious rug under his feet, a warm bath after a long day, etc. If he doesn't try to hoard it, it doesn't really fit with orange.
I guess he just doesn't feel strongly enough to truly be a wielder of a ring.