1) We do know (more or less) how the matchmaker worked as of December or so 2014 (based on comments made in these forums by the developer who wrote the code ... I don't think it likely we will ever get a better information source than that).
Given that PGI has spent almost all of their development effort in the last 6 months on CW ... I think it is reasonable to assume that the MM has NOT changed in that time frame (despite apparent conspiracy theories to the contrary).
Can I guarantee that? No. But it seems likely.
In addition, from my personal experience, I have noticed NO change in matchmaking for the matches I am in, for at least the past 8 to 10 months or longer.
2) KDR is irrelevant to the calculation of Elo or matchmaking. So is damage done ... or any other in game performance metric. Keep in mind that these metrics may not indicate whether the player actually contributes to winning the match or not. I've seen a player in a Timberwolf score 5 kills, 3 assists, over 1000 damage ... most of it after the rest of the team was dead (at least 4 of the kills happened then ... and a lot of the damage as he sprayed lasers all across the opponents).
Do any of these stats matter in a game? No. The only thing that matters is whether you win or lose.
As a result the MM tries to populate the teams with about equal Elo value players across weight classes. It then calculates which side it expects to win based on Elo. The rewards for the match depend on the actual win/loss outcome of the match when compared to the prediction. If you win, your Elo will go up .. if you lose it goes down .. but the amount of change depends on the probability of the predicted outcome.
What this means is that you could hypothetically win one match and lose three and your Elo could still be higher after the four matches than before you started. Similarly, you might win three and lose one but your Elo might drop. However, over the long term ... if the MM is placing you appropriately, then your W/L should approach 1. If you are getting better at playing the game then your wins will likely go up .. and so will your Elo. If you are leveling a new mech then you might not be as effective, you might lose more often and your Elo drops.
3) Personally, I am either in a good place with Elo on heavy mechs or I have a higher tolerance for bad matches (or perhaps the larger number of heavy mech players just makes it easier to find more folks in the same Elo range as I am) ... whatever the reason, I don't get very many matches with people doing their own thing. On the other hand, I will almost always state in team chat ... "Stick together, focus fire, have fun!

Mediums have also bee pretty good recently.
Playng my lights might be a different story but I also tend to take some chances I shouldn't in light mechs just because they are so much fun

Edited by Mawai, 14 July 2015 - 07:38 PM.