To me, Rafa is not playing well. That's it. It's not the end of the world and IMO, he's due. This is his first off year and he's entitled. Life is about ebbs and flows and what happens today will be forgotten tomorrow. It's not that big of a deal.
I don't think Rafa played that horribly, but sometimes you don't get the breaks. Feliciano played very well and didn't back down. I think that's key. Goffin had the match and backed down. He lost. Grigor had the match and also backed down. Had those two held their nerve it would be a totally different conversation.
Personally, intimidation is a large part of the game. When you win and gut matches out it adds to your aura. If you don't, it depletes it. I don't think any player is that good or great. There are a lot of matches won that should have been lost and vice versa. What's most important on the day is the response of your opponent because no one plays at their optimal level every match and many times The Big 4 escape. But, if that person on the other side doesn't buckle, as happened with Rafa, but not Novak and Grigor, there would have been three casualties, instead of one.
That's how I see it. I see the top players get away with a lot because of what they've done in the past. A double break in the decider? The opponent choked. I knew Grigor was going to lose that match because while he's talented, he's not confident. And Goffin playing Novak and winning was a difficult situation. Maybe the next time it won't go down that way, but it will depend on how the underdog handles his nerves. That's what it always comes down to, IMO.