It is the most reasonable attempt yet, but I still see too many unanswered questions about security of the connection - again, if the government can get access with a warrant, what is to stop a hacker with access to the network from also listening in? There is too little information about how this should be implemented, without breaking things or allowing unauthorized parties (rogue admins, hackers) access.
The solution itself is almost reasonable, but the checks-and-balances need to be in place first and auditable, before such a solution can even be thought of.
They need to prove that they are trustworthy and, until now, they have only shown that they can't be trusted as far as you can throw GCHQ.