Viana and Amorim describe their relationship in exactly the same way that Pep and Txiki describe theirs. That bodes well and hints at Amorim to replace Pep.
I think it's the right thing to do. Pep's a one off and trying to cling on to his legacy would be a mistake in my opinion. Liverpool seem to be transitioning ok post Klopp having started afresh. The absolute worst thing anyone could do is copy United's decade long mourning period post Ferguson.