The reason for maxing out my Q first is mostly for damage and early armor penetration. When I first played Jarvan, I maxed out E but found that I didn't get quite as much damage and harass with it. As the E skill uses ability power, I found that maxing Q which uses attack damage was much more effective. Adding to that, I usually laned against more tanks. The reduced armor was really effective.

Great build imo, really close item build to the one i use, only have one question, why don't you max out your E first? Its passive, even nerfed is still quite good..