Ok, you want constructive criticism?
If you want to curb or significantly decrease quitting, give players the option to hide all stats outside their ranking.
You make players individual records easily viewable online via website, app and in-game, then you incentivized a dick-measuring contest. To the shock of nobody (aside from 343i, of course, but they're clearly the last to consider anything), players are happy to quit when it means making their e-peen look bigger at a passing glance.
This is the direct result of a design philosophy built around catering to the least important populace in gaming ('pros').
It's pretty easy to have your cake and eat it too in this case. Let the 'pros' show off their stats as much as they want, let anybody who wants to set their stats to private do so. Assuming 343i's matchmaking means fuck all (spoiler: it doesn't, take it from a platinum that's been going up against diamonds and onyxs most of the weekend... but let's operate on the premise they make it functional), then the only front-facing information necessary is the rank. It's enough to show whether you 'belong' in the match or not, and give a general idea of your skill level relative to your peers, teammates and opposition.
But for the love of god, fire every single person involved in the multiplayer UI at 343i. Don't even bother giving them the courtesy of cleaning out their locker. Just dump their shit somewhere over Siberia and let them go look for it, it will keep them busy for awhile and spare all of us ever having to experience their work again. Hire some kids out of the Art Institute at a bargain rate, give them a copy of Reach and tell them to copy it as closely as possible.
You give players the ability to hide a K/D they're shy about, you remove the incentive to bail on a match where 343i's currently wretched matchmaking ensures their K/D is going to get the prison shower treatment.
Simple.
Extra points if your provide players with the option to wipe their stats back to zero and erase all the hellish history of being bent over and violated by your goddamn worthless placement and matchmaking systems.
EDIT:
Bonus constructive criticism: Leave your 'vision' or whatever at the door, and scrap last-shot kills in Warzone. It's been panned by pretty much every community I've seen discuss the mode. It's terrible, frustrating, actively disincentives team coordination, and - given the impact that 150VP bosses have on the outcome - makes Warzone a roulette wheel instead of a skill-based enterprise. Considering the mode is already significantly impacted by the cards that players have at their disposal (which is obviously random), I'd say limiting other random factors is a necessity.
If you don't want damage dealt to be the deciding factor, then use DPS and change the color of that yellow icon that denotes their position on the map to the color of whichever team is dealing the higher DPS at that moment. Whichever team is dealing the higher DPS at the time of the final shot, earns the kill.
That way, if I'm on the red team and I see that the boss is at half-health and his icon is blue, I know I need to get my ass over their and maybe burn a req card to try and even the odds. Or maybe I need to decide whether to deal damage to the boss, or try and take out the guys dealing the damage.
But at least I fucking know who is going to get credit for that kill instead of spamming shots at the boss and crossing my goddamn fingers.
