Ederson is a very good goalkeeper who will be a huge improvement on what we had last year. Stones seems to be getting the brunt of the stick from plenty of people but he's a lot better than he's getting credit for. Kompany is the best in the business, bar none. He finished the season having played 9 on the trot and was excellent throughout. Otamendi, having Kompany alongside him also started to look like the real deal. Kolarov has proven he's a more than capable stand in CB if required. Gundogen was unfortunate with his injury, which wasn't the same as previous and will be back to 100% by the time the first ball is kicked. Toure will be a bit part player, and an excellent option to have I certain games. Fernandinho, whilst not having the best seasons is still a quality player to have in your ranks.He is right. I'm wary about the core to our team. Ederson is unproven. Stones, otamendi, Kompany and kolarov isn't good enough for me. Gundogan is always injured, toures defensive contributions are about as good as bravos keeping and Fernandinho had a bit of a shit season.
Added to that two new fullbacks, Bernardo Silva and potentially Sanchez then I feel your fears are unfounded.