Raw damage isn't that important. How you play and how that damage is applied is much more meaningful. If you have 125k damage and 30 kills, and someone else has 200k damage and 21 kills, who was smarter with their damage? I see huge damage numbers and low kill counts all the time, because it's just AoE that doesn't really threaten specific targets.
Also, if you play objectives and try to win, you might find your damage numbers a bit low. You're not going to be DPSing a lot if you carry the ball or run ahead to receive a pass and score. Your damage might be low if you're guarding a turret alone for 50% of a game. Etc. How you play means much more than any specific number.
I disagree, kills is pretty meaningless - it just means that you damaged somebody who eventually died. The best way to get lots of kills (and lots of raw damage) is just to throw out lots of AOE but that doesn't mean you have been being particularly effective. Similarly, pressuring a healer (like a Sentinel should be) will put up a lot of damage without necessarily doing many kills - but that is still very important. Really, most of the statistics are quite meaningless (although somebody doing >75k damage, 0 protection and 0 healing is pretty bad almost regardless.)