Current MMR system on Deathwing and Ragnaros is broken. For example if you want to play different comp then the one you have started and you invite different person to the team with 2.2k MMR or so while you have 2,6 or higher your MMR will share and it will make ~2,4k MMR. You will gain less rate (+4, +5) but if you lose it's -17 or -20 even if you face enemy with ~2.4k MMR as its ur current MMR. This should not be considered as "MMR Abuse". You should make it just like before without MMR sharing thing. Also that person that you invite in team if its high rated will gain less MMR but more personal rate so at end his personal rate will be higher then MMR. I can show you couple of screenshots of my in-game MMR 2,7k same as team rating and on website it says 3.3k ? Makes absolutly no sense.