.. the best way to address that problem would be for the EU to define the standards and the process to be followed...
This, absolutely this. In order to force someone to turn over information, I have to have a valid subpoena issued by a court with jurisdiction. The fact that they just punted this to "you figure it out" means Google is given arbitrary discretion on how they can fulfil this, and the recourse to disagreeing is to take them to court and sue them again.
If you're going to give someone a right enforced by the government, then you should provide the necessary process to issue a "strike-records decree"...
BTW, Google still tells employees not to talk about this stuff in public, because Google has to so carefully watch its steps. (Disclaimer, I used to be a Google employee this year)
The problem is also the consent decree that says "anything that Google says, it has to actually be doing"... which can end up really nitpicky if lawyers want to be... and "my various governments" are all looking to catch Google for something, anything... so, they are being a bit nitpicky...