The changes we've made are an easy excuse for poor defending. Whilst consistency helps with a system, if we want to be one of the best in the world we have to be consistent despite rotating the squad. Stones has made too many errors. He's young and developing so you can give him the time to do so, but there have been too many errors in general from our defence. We looked a lot better against Arsenal, albeit there was still switching off to allow their first goal.
Crucially, and what the media are missing, is that our defence is all about keeping the ball high up the pitch. We were so good defensively in the second half against Arsenal because our attacking players hunted the ball and our defenders mopped up their aimless clearances. That's how we need to defend. We've been slack on this recently, we didn't give them a sniff second half because our whole team defended from the front. When we do it consistently, Stones will slot in comfortably.