You may be right. I hope we'll have Stones available and in top form. But we may be underestimating our defensive record with Laporte. We have conceded 13 goals in 21 league games. That's excellent! Before Leicester, we had conceded 9 goals in 18 league games. That's outstanding. We conceded 3 goals vs Leicester because we were 4 goals up and stopped to play (and also because we didn't have Rodri and Walker).
Now imagine that we had Stones (2 starts) instead of Laporte (17 starts). You say we look "a lot more solid" with Stones and Dias. Would you translate that in numbers? We had conceded 9 goals in 18 games prior to Leicester. How many would we have conceded with Stones and Dias? 3 goals? 5 goals? 7 goals?
IMO, it's a myth we are "a lot more solid" with Stones and Dias. It depends on their form. Dias was a world beater last season, but played too many minutes and lost a bit of form (both with us and Portugal). Both Stones and Dias were poor in the CL final, especially Stones who was all over the place. And now people want us to believe Stones is the key to winning the CL? They may be right! But I think the consensus is a bit premature. Time will tell. The most important thing now is that Stones regains form and stays fit for more than 3-4 games.