I've actually been anticipating the whole Wakana/Yuina pairing for some time now. Basically ever since they joined forces to push Ayaka and Sora together. I agree that they are a complimentary match, and I feel like that was intended by the mangaka as well. I don't know if anyone else noticed, but like Sora and Ayaka, Yuina and Wakana are opposite signs. Wakana is a Sagittarius (my sign as well, and she totally is), and Yuina is a Gemini; those two signs are known as opposite signs of the Zodiac. In other words, they tend to have certain qualities that the other lacks. Furthermore, I feel like Yuina supports Wakana's confession not only because she wants what is best for her friend, but also because she knows that Waka needs closure before she can move on to someone else cough Yuina cough. Given how bad Wakana is at reading signals, though, and how much of a tease Yuina is, it may be a while before we see these two genuinely get together.