h ttps://gamefaqs.gamespot.com/boards/276479-overwatch-2/80480335
This is just a mere fraction of various polls alone asking about 5v5 vs 6v6. In all of them, 6v6 is usually the overwhelming majority vote.
The game was built upon 6v6; its the sweet spot as described by the Jeff Kaplan who made this game in the first place. (with others of course)
There are several videos by both casuals and pros alike saying 6v6 was better for the game. There was only one (to my knowledge) popular OW youtuber who said 5v5 was better and the video has majority dislikes, along with people stating various reasons why 6v6 is better.
There are several threads in both the forums and reddit stating that 6v6 has always been better and healthier.
5v5 has brought nothing but issues including, but not limited to supports being broken due to a giant health pool being removed from the game and allowing them to allocate their healing to the sole tank of the game, the support passive being added as a result to 5v5 and making Anas nade used more offensively than used on herself which results in constant anti-healing, Zenyatta being nerfed due to discord being slapped on the single tank for the whole game and getting immense value, DPS being undervalued due to them gaining less ult charge on tanks while other classes have good passives to compensate, the NEW dps passive that makes tanking miserable and acts as a mini Ana Nade, and various other reasons.
It isn’t a biased assumption when the overwhelming majority online prefer 6v6. Blizzard is too prideful to ever revert an update and only builds upon mistakes and hopes it works out.
5v5 has been nothing but detrimental to the game and will continue to do so. The reasons above are a clear indication.
At the very least they should make a 6v6 arcade playlist experimental with adjusted tank health, similar to that of 6v6 and no passives. That would give them important data.