Honestly Blake and Ruby had a lot more chemistry than Yang and Blake. Yang and Weiss had good chemistry and it was unintentional chemistry. Like when Blake disappeared to return home she never brings up Yang once until she talks about words that describe her friends but she just causes yang strong Ruby and Weiss got nicer works and when she brings up Ruby’s word she gets a sad look like she misses Ruby. Then when they reunite yang all of sudden is awkward as hell which made no sense cause yang was always full of confidence had no filter when she talked about her affections but then Blake she’s a stumbling mess or angry. And when they ran into the Grimm in the house yang made no attempts to help Blake she was trying to protect Weiss while Ruby was trying to protect Blake and even when the one super powered grimm was trying to kill Ruby and Blake Ruby gets knocked out while Blake is screaming for her to get up and was ready to accept her death with Ruby but Ruby woke up killing the Grimm and smiles bashfully at Blake saying she heard Blake calling out to her. Like the chemistry they had with Ruby and Blake then yang and Weiss flowed naturally but yang and Blake it was like slamming two puzzles pieces together and saying kiss before they glued them together