1. Thomas is hurt.
2. They have a lot of new guys on the roster(Green, Wade, Calderon, Rose, etc..) and as you said they just lost their second best player.
Chemistry isn't going to be great and Lebron has had awful spatches before. I think they eventually correct this but there no chance in hell that that team is winning a ring. If Hayward didn't get hurt, they might not even go to the finals.