The decision to create a tank army (armoured corps in Western terminology) is an indication that Russia really does fear attack from the west and is preparing to defend itself against it.
In short, Russia has finally come to the conclusion that NATO’s aggression means it has to prepare for a big war.
As a historical note, Dominic Lieven’s book shows the preparations Emperor Alexander made when he realised that, sooner or later, Napoleon was going to come for Russia. And everyone knows how that ended. As Field Marshal Montgomery, who had more experience of big war than anyone in the Pentagon or White House today, said: “Rule 1, on page 1 of the book of war, is: ‘Do not march on Moscow’.”
This is what the light-hearted decision to expand NATO, “colour revolutions”, regime changes, cookies on the Maidan and incessant anti-Russian propaganda has brought us to.