We know that party size in Hero League is a pretty heavily debated topic in the community. We've also had frequent and lengthy discussions on this internally. (The latest being as recent as last week!) In all cases there are those who passionately argue that Hero League should be limited to Solo Queue, but also those who would prefer to keep Duo Queues, or even expand the limit to three-player parties.
We don't currently have plans to make changes to the party sizes allowed in Hero League, but know that it's an active discussion we're monitoring both internally and in the community.
As far as MMR is concerned, we still have no plans to implement complete resets. However, we are still going to increase uncertainty with each new ranked season, much like we did for season 1.
Taken from here http://us.battle.net/heroes/en/forum/topic/20748624776 .
1) Allow players to reset their mmr in a mode every six months for free. Not only is there frustration with getting stuck (funny as the thread seems this player might be considering quitting because of this http://us.battle.net/heroes/en/forum/topic/20748645367 , not really because of the mount; he is more likely to accept not getting these mounts if he could reset the mmr on his stacked account to truly test where he belongs and isn't upset just because of the mount), there are repeated claims of smurf accounts settling at significantly different mmrs from main accounts. Give players the periodic chance to test where they would end up on the ladder with a clean slate. It appears whatever loosening of mmr is done seasonally isn't enough.
2) Allow players to queue in parties of 3 for Hero League again. If I recall correctly the main reason for limiting HL to solo and duo was the large difference of mmr or rank in some parties causing frustration among other players. There now appears to be a rule that doesn't allow players to queue for HL in a party having much higher or lower ranked members so that problem is addressed. Some might not like that players would be able to queue as three in HL but I don't think many will stop playing over this. I think this change would do some good for others, promote and coincide with a more social experience that improves enjoyment. It's typically not the solo queuers who don't put up with things in my opinion.
Overwatch doesn't seem to have any limits (edit: now they are limiting the skill differences within parties, but not the number of members). If voice chat is coming to HotS as well then it's all the more reason to allow players to queue as three again.