I am a little confused about the arena system, especially how points are given / taken. The last couple days I played 3s with 2 of my friends a hunter and a holy pally. We got to 800 on the first day and are now around 1200. Gear isn't the greatest, haven't replaced my heirloom dagger yet and Rogue / Pally / Hunter is a bit of a strange combo.
We constantly have teams with a matchmaking rating that is equal or in the Range of -/+20 win 30-48 points against us. We however have matches against Teams with MMRs significantly higher than us (1400+) and we gain less than 10 points.
We don't lose much points either but gaining less than 10 points per match makes for an tedious grind to the 1500s so my question is how and what determines how much points we lose or get and how much points they lose or get.
The matchmaking rating is what, well, determines who you face in a match. It's based off gear, last season's ratings (I believe), and a few other factors. It does not, however, determine team points gained or lost. The MMR will go up and down independently of team rating changes.
Team points are based on the team rating. That's why you could face an equally ranked team in the 1600s, according to the MMR, but end up losing 15 points simply because they're a newly formed team and are around 1000 team rating or lower.
It really sucks, simply because you're literally taking 3 steps forward and 1 giant leap back to end up where you started. But hopefully it'll smooth out later this season. It also seems to be the worst around 1500 MMR. Once you break into the 1600s the points get a lot more even.
EDIT: Ah, yeah. Forgot to clarify that the difference between your MMR and your team rating will influence point changes. That is why you get 48 points for a win on a fresh team and only lose 0-1 points on a loss.
The points given/taken are based on two factors. How close your MMR/their MMR is to their actual rating and the confidence the system has that that team is infact that MMR.
The confusing thing at low ranking is that you can easily have teams that are very new (say under 100 games) who are really rated 1850+ but who's MMR might be somewhere around 1600 or lower depending on the number of games played and who they've been matched against.
For example I noticed this happen while playing 2s with my new partner earlier this week.
Our actual team rating was around 799 after 25 games. Our win/loss ratio was about 2:1 and over those 25 games we had gone from 'undetermined' MMR to somethin glike 1750.
At one point we had a listed MMR of around 1575 and we beat a team with an MMR of 1550ish. We gained 47 points, they lost 12 to 18 I forget exactly. To them it doesn't make sense to see sucha big difference in won/lost points. Had we fought them again and lost, we'd have lost 0 and they might have won 10 points or so. The issue, again to reiterate, is that in this example the system has a high degree of confidence that the 1550 is going to have a win/loss ratio of about 50% at 1550 rating. The system however has evidence that my team can and has won at least 50% of the time against teams above 1700. So even though our MMR at that instant was similar, the system adjusts it upwardly very aggressively.
Basically your MMR determines who you are matched against, and your team rating adjusts not based on the team rating of the team you just beat but based on their MMR versus your team rating. If their team is 750 rating, your team is 750 rating, but both of you have a 1750 MMR the winner gains 40ish points the loser loses nothing. As long as you can maintain your MMR your team rating will eventually mirror it if you play enough matches.