People will probably dislike Yuri even more so for events after ep 11 then... she will basically go all out to get what she wants (Yano), hurting everyone else in the process.
The problem with both Yano and Nana2 throughout the majority of the manga is that they are stuck in his past. For Yano, he still loves Nana1 even though he knew she cheated on him, so it's tormenting him. Yuri did not help this case by confirming that the cheating was true in order to hurt both Yano and Nana2. For Nana2, she's inexperienced and cares too much about stuff that happened before they went out together, being immature. But dont worry, she will get over it
Sure, all the characters are weak and flawed, and I'm not calling Yuri a whore. But she does indeed have a very selfish personality that only cares about herself. It was as much Yano's fault as Yuri's that they slept together.
As for Nana1's cheating, she likely did it because she is a weak person that is always dependant on others. So she always needs someone to be there for her.
As for Yano, his distrust and paranoia to confide in his loved ones is his undoing (caused by experience with Nana1). I don't buy into the sacrificing for others sake/not wanting to hurt loved ones BS. Loved ones are there for a reason. His choice not to contact Nana for 4-5 years is one big mistake.
I look forward to his reaction when he finds out Nana2 is now Takeuchi's girlfriend. If he accepts it like man, I'll truly be impressed and might even root for them to get back together, but if he acts like a whining bitter bitch like in the early years, I hope Nana2 stays with Takeuchi. We'll see what happens I guess...
You should wait until all the eps air, or read all the manga and then give your opinion on the characters. I think the author really went all out to make the readers dislike the Yamamoto sisters... At least in Suzuka we see Suzuka's good sides, I do not recall one good deed that Yuri does to this point, the bad ones keep piling up. And they're now 20-21 years old