I think the time factor also plays into it. Those that get to play more have a number of categories bumped up, not to mention all that practice time.
Nrshida's fighter ranking at about 8.5 hours playing time,
Score Rank
Kills per Death + 1 0.59 637
Kills per Sortie 0.36 690
Kills per Hour of Flight 1.87 798
Kills Hit Percentage 1.16 1013
Kill Points 886.86 583
His nemesis's fighter ranking same day at just under 75 hours playing time.
Kills per Death + 1 0.78 387
Kills per Sortie 0.49 399
Kills per Hour of Flight 2.92 441
Kills Hit Percentage 4.74 340
Kill Points 38067.60 2
The kill points is a huge difference, and you just need time to build that one.
K/D and K/S is really two factors. Skill and style. The better fighter will have better numbers here, but if you fly in furball to the death all the time it will bring those numbers down. Those that fly careful..... AKA as nrshidas nemesis in this instance can inflate those numbers a bit.
Kills per hour of flight, this is another number that can be inflated due to time playing. Lets say you find a single great fight where you can get a bunch of kills every ten hours. Nrshida gets one such fight were his nemesis gets 7 of them. In these opportunities your kills for that hour can be very high over your average and so bump it up.
Hit %, is just aim right? Well you can bump this one as well just by hitting buffs. They take a lot more rounds to drop, and as a bigger target are much easier to hit. Find a few dive bombing wonders and rake the crap out of them as they lawndart and your hit% will climb.
Luckily rank is only important in the game when it comes to CV groups, which is too bad but there it is. Just because someone can tweak there rank, or is willing to spend the time to do it certainly doesnt make them a better fleet admiral.
There are a bunch of loop holes in the scoring system. There will always be those that will look for and exploit those loop holes making any type of ranking/comparison a waste of time. I don't think there is any way to make it "fair" as there are just too many factors involved due to time, styles, arena numbers and even the maps that can help a player tweak his/her rank.
I look at it this way, if a beat a player consistently, no matter their rank, I fly this cartoon game better than them. Unfortunately, there are not very many I can beat consistently