IMHO putting time pressure on Britain is good news. The lack of progress so far is proof that the new prime minister Teresa May is treading water and stalling.
Why?
Article 50 gives the EU all the advantage. If May had the kind of backbone of a Thatcher (which she does not), she’d invoke “rebus sic stantibus” instead. Her being pro-EU, she would likely use this bullying announcement by Barnier to try to utterly reverse the referendum.