Mate, with respect, this is at best a very bizarre post.
How don't they compliment each other? One a 'stopper' who puts his body on the line, old-school if you like. Almost Vidic-like. Stones is more Ferdinand like, more graceful but not as good a defender (no-one seems to be noting that Stones watched Giroud slowly leave him for the opening goal, failing to track him).
In short, they've shown they are a very good blend of talent, Jagielka and Stones.
We conceded only 39 goals in Martinez's first season. Jagielka and Distin. 40 goals conceded for Moyes final 2 seasons.
If that's not the definition of a mean defence and a good partnership, I dont know what is.
Based on the game against Arsenal? I'd agree, don't get me wrong, but it's hardly a decent gauge of where they are at as a partnership.
I don't think we should be fearing Jagielka's absence, but at the same time to dismiss his good form over the last 12 months and raise concerns with his ability to form effective partnerships is, as stated above, bizarre.