It seems to me that both "sides" of the conversation are employing double standards. France backing Russia to the hilt is no more acceptable than Germany backing Austria to the hilt. Either they are both fine or neither is. Now, the invasion of Belgium was precisely the kind of insane German military move done with no regard for consequences - but Grey *had* warned the Germans that British intervention would happen out of any German attack on France. However as we know, France only became involved after Germany was forced to react to Russian mobilisation (and we have the records that Nicky and his generals perfectly knew what such mobilisation would entail for Germany) so why is it okay for Russia to do this, and not okay for Germany to react?This is again a double standard, when Germany threatens to fight France and Russia on behalf of AH it them trying de-escalate things, but when France and Russia threaten to fight Germany in response to that it's because they sought a wider conflict?
On top of that Germany's actions bring Britain into the war!
I'll be the last person to defend Imperial German diplomacy. They largely backed themselves into this corner, and especially violating Belgian neutrality was always going to end in one way only. But if the idea is that Britain is "the good cop" trying to maintain the status quo in Europe, then they failed by not issuing warnings to all parties. And if the idea instead is that Britain was doing its interest by protecting the weaker continental power (France) against the stronger (Germany) then it is yet another example of the Great Powers of the time being "Great Irresponsibles" and Britain too would share a part of the blame for the conflagration. Tertium non datur.
Now, to go back to the OP (which has been severely neglected after this tangent, I feel) the issue is that Germany (or any other country individually) playing nice does not mean things will turn out alright. Even if Germany magically gets its act together, prevents leaks or diplomats sitting on messages because they went against their agenda etc, they will still need to react to what everybody else is doing. You need fundamental changes in Austrian and Russian diplomacy especially if you want a different outcome in the July Crisis. What Germany can do is play the game more responsibly and honestly... and likely end up at war anyway.