Why the hell is Morell talking about the mainstream press? 
This is about the intelligence community, congressional committees and the special counsel.
Remember, almost everything we knew about Watergate came out of divulged grand jury testimony, etc.
If this isn't released, either publicly or as a leak, we're unlikely to know.
But we have all sorts of meetings with Russians going back to 2013 and before (even 2002), Russian relations that have been denied or described as something that they weren't - especially the Jun 9, 2016 meeting & Trump's lost weekend in 2013 where he was doing a Trump Tower Moscow deal tied to his pageant, and multiple versions of "facts" for example here and here.
Jared Kushner, Wilbur Ross, Paul Manafort , Jeff Sessions and Michael Flynn all left Russian connections off their security documents - Manafort & Flynn being charged for it already. And then there's Carter Page who's a big loudmouth goof just dripping with inadvertent inconsistencies and damaging info on others. A few others like Priebus in the mix as well.
And then Mueller now has 15,000+ emails to use to compare with sworn testimony looking for any other deviations. And at least Manafort's phone that was hacked by FISA or similar order.

There's been plenty on Cambridge Analytica tied to Wikileaks tied to Russian hackers & social media spammers, plenty on hacking DNC & DCCC & private gmail accounts (Podesta, et al)

This is not "speculation" - Papadopoulos and Flynn have already pleaded guilty, and their testimony almost certainly extends to Russian interference of US election 2016 (*not* the much more limited "Russian hacking" bit you propose). Manafort & his assistant have been charged. All roads seem to point to Rome at this ppoint - I've no clue why Morell is out pretending it doesn't, but in general the intelligence community - FBI, CIA, NSA, etc. - fucked up bigtime, so maybe some of them want to hide their shame. Bad approach. We can't afford more bullshit.

Almost all we have is speculation because contrary to right wing claims Mueller is a straight arrow who is running a very honorable investigation. There are no leaks from his team. There's no Mark Felt feeding damaging information to a couple of rookie reporters at the WP or NYT. Or Ken Starr's investigation that leaked like a sieve because Starr had a strong partisan motivation to bring Clinton down. We'll need to wait until the investigation is over to see what went down.