It's so hard trying to judge a pilot's skills just based off their stats. Knowing that points don't matter is easy enough, but then evaluating their kill count to missions played ratio was hard. I think good pilots who played TvT more often had somewhere between 13-20 kills per mission. Anything above 25 was probably a coop player. Primary and Secondary accuracy helped a bit, with experts hanging around 10-15% (the beauty of ms, you miss so much lol).
Dunno, it's really hard to evaluate because being the host (or mainly ping) in a TvT can make a huge difference. Usually the best I would ever get was around 300, and that's no fun against a team of pilots who have 100-200. Also, it really depends on who you play. I can say from experience that playing in a 4v4 against squads like DW and DA did not result in a lot of kills. Usually in normal TvTs squad members play together, and if you were unlucky enough to be stuck on the other side with the newbs (back when we still had a lot of newb pilots), it was a great learning experience, but nothing to help your stats lol.