I believe his performances at LB last season being bad are exaggerated. If I recall the issue was that he was right footed and playing LWB, so we really struggled for creativity down that side due to width, or lack thereof. Not that he was bad, per se.
I'm glad he's looking back to his better self. Hopefully this is like the Aguero/Jesus dynamic but with him and Walker, whereby whenever the understudy starts to look like a threat the main man comes back with a point to prove. I like Danilo a lot, but a fit and firing 100% Walker is a truly top class RB who'd I'd rather in the team.
But as it is, the more good games Danilo has the better. He's a significantly better attacker than Walker, so having him as rotation, competition, and variety only does us favours moving ahead.