Probably the best decision(s) they made for the movie
Just reading the play script...it is so full of awkward and rushed dialogue, inconsistencies with characters and situations, and several of the scenes are misplaced. Whoever decided that "Cool" and "Gee, Officer Krupke" should be in the scenes they are in the play...that alone shows the author's writing leaves a lot to be desired. Arthur Laurents, I am looking at you.
Yes, I have heard the argument that "Gee, Officer Krupke" is supposed to be an angry song. Yes, I have heard the argument that "Cool" was meant to show Riff as a powerful leader. But those arguments still do not match up, and I'll tell you why.
The Jets may have been angry when singing "Gee, Officer Krupke," but there were still comical elements in the song that's guaranteed to make people laugh. I'm not saying it's a happy-go-lucky song, but it's still very comical. After Riff's death, we are not supposed to laugh. The enjoyable moments were supposed to be before the rumble, and now that it's happened and lives have been lost now it is time to get serious. The movie did a wonderful job of making this clear but the play did not. And just the general way this scene was written, it just didn't have that same effect on me. It didn't seem to me that the Jets were really that concerned about what just happened, that they even cared. They just didn't seem to be reacting as urgently and drastically as they should have been. Unlike in the movie, where they were going insane and ready to tear the Sharks limb from limb, and where "Cool" actually applied to the particular situation, they showed little worry about the after-effects of the rumble, they sang "Gee, Officer Krupke" even though it had nothing to do with making sure they got revenge on the Sharks, and then when Anybodys shows up then they decide to take their situation seriously. That seemed really forced and out of place.
Which brings me to my next point; of all the Jets they could have chosen to take Riff's place as leader, they chose Action. And they don't give any early hints or indications that Action is going to mature enough to be a good leader when the story calls for it, Oh No!! He goes out of character and immediately becomes the cool-headed, authoritative type for no reason when throughout the entire story, he is consistently portrayed as hot-headed, always ready to fight, always yelling and using his fists, and he would NEVER make the good decisions the writers forced him to make. This is what I mean by character inconsistencies. Action didn't become the way he did in the second act because he had the character development for it, he became the cool-headed authority because the plot needed him to be.
Here is where the movie got this right: They, as we know, put "Gee, Officer Krupke" after the dance and before the war council, and they put "Cool" after the rumble which, as I said, applied way better to their current situation and actually made sense. AND, they kept Action in character and chose a better, more realistic candidate to replace Riff: Ice. This character should have been in the play!
Another song in a different scene I sort of have a problem with is "I Feel Pretty" taking place after the rumble and before Maria finds out that Tony killed her brother Bernardo. I'm not as nit-picky about this scene as the other two I mentioned, because you can't really blame Maria for not knowing the truth yet. But at the same time, the tone of this scene is still inappropriate if it immediately follows a horrible, gut-wrenching sequence of violence. And in the back of our minds we know that Maria's happiness is going to be horribly shattered when she hears what Tony did, and it's just more torture on the audience. At least in the movie, when the song took place in the bridal shop, you still had hope that everything was going to work out well for our two lovers. Seeing her perform it after the rumble is just torture, and for the same reason I gave for "Gee, Officer Krupke," there's not supposed to be more fun to play out through the plot. After the rumble, it's serious business.
The dialogue also flows better in the movie; when reading the script most of the lines were shorter, more choppy, and just plain awkward like they've turned in the first rough draft. You could just tell the writers could have worded the lines a lot better. In the movie, I felt the lines were almost perfect.
I'm not saying I didn't like the play, but I sure as heck liked the movie a LOT better than I did the play. I still consider West Side Story to be my favorite musical of all time, and Tony is still my number one dream role onstage. Hopefully, if I even do get the role the director might make similar changes to the script to make it more like the movie. I know that's not likely to happen but I can dream.
I heard they put on a revival of West Side Story a couple of years ago if I'm not mistaken. All I heard was they gave the Sharks more dialogue in Spanish, and dubbed the entire "I Feel Pretty" number in Spanish. I don't know what else they did, but I don't think it included putting "Cool" and "Gee, Officer Krupke" in their proper places. You would think after making the movie and seeing the difference of the plot's improvement, they would have made those same changes to the play so it would have made more sense. Unfortunately, they still haven't, and that just really gets on my nerves. At least I still have the movie to enjoy; the people who made that at least fixed those mistakes.