Andy was asked about the racquet on a Scottish news interview, and he said something along the lines of it getting the anger out and meant he wasn't letting it simmer. He'd have to pay a fine, but it was worth it, because he played better after that.
I'm not a fan of racquet smashing myself, but it doesn't particularly bother me either. I thought it was interesting that he chose to simply explain it, not to apologise for it. I also think it's a bit silly when people say he should be more calm and collected because he was winning, and so on. One of the reasons he, and the rest of the top players, are so successful is because they believe they should be getting all of those points back, and not making silly errors. It's easy to be philisophical, or arguably realistic, about his chances of winning a particular point, but being a bit unrealistic about what they can achieve is driving them to be their best for every point in every game in every match.
Andy smashing a racquet, or belting a ball as he did today, has to be better than stewing on the frustration like he used to do. The key is how he deals with the aftermath. Does he stay angry and play badly, or does he get better? If it makes him better, which it did against Dolgopolov yesterday, and also against Stepanek today, there is no issue. In my opinion the Andy who stews on errors for ages is gone, and has been replaced by a young man who is much calmer on the whole, but still has the fire that gives him and the others in that elite group, what they need to win.
It seems to me that the question is simple. Do we want someone who sometimes needs to let his frustration out at the expense of an inanimate object like a racquet to get the best out of himself, or do we want someone who rants at himself for points at a time, which can then stop him thinking clearly enough to get out of a tight spot? I know which I prefer, because you can bet that the Andy of old would probably have lost to Cilic in the USO, and may well have lost to Stepanek today.