Firstly, I always compare defenders to players like Baresi, Maldini (OK not the same position), Cannavaro, Stam, Rio, Vidić in a box, Kohler, Thuram,......, so that's why I sound harsh a lot of times. I don't like the way people say OK, he is not TOP, but compared to today's defenders we can say he is TOP. I don't think it's the right way to do it.
Now, look, Hummels just wasn't good this season, I could say it has nothing to do with the price, he just wasn't good and in a high line in the Prem we would need to have a TOP TOP midfield to be able to play with him.
Because I compare CB's to the players I have mentioned I just can't tell whom I would like to bring. I prefer younger defenders, but we have to many of them (actually almost everyone is young for a defender). I didn't watch enough football to be able to judge, but I was watching BVB games (it was often on TV) and I was watching Real as it is also often on TV (and I stream the big games) and that's why I am against these to players (with Ramos it's actually the whole package which is annoying, even if I would prefer him instead of Hummels quality wise, but I don't like how he behaves). The CL games I've seen just didn't really impress me when it comes to defenders.
But I am not arguing about 10 CB's, I am mentioning one, now also Hummels, so let's say 2.
PS
No, I wouldn't stick with our injury prone defense, we do need one CB.