I've been wondering this for a while, and now I finally have a chance to to put it to the public. I was thinking about it and both are pretty much (and have been) on the same speed of achieving their goal through out their respective series. I personally believe at this rate, Naruto will become Hokage before Luffy becomes pirate king. However I only think this because I think that there are more king candidates in OP than people that have to go through Hokage. I think Kakashi would be between Naruto and Tsunade. His reign would be pretty long though. I also don't think that the next pirate king won't be caught for a long time after his achievement.
What are your thoughts?