Automatically convert non - elementary apps to elementary native

Applications such as Firefox aren't perfectly integrated within the elementary os graphic environment. I'd suggest to create a script or something like that that takes the source code of the app and modifies it in order to make its appearance like in elementary native apps.
Then these modified apps could be (automatically) compiled and put in a brand new ppa where the appcenter could search from. Of course, these apps need to be tested and the user must be warned before using them that something could go wrong.
And so the user need to choose whether to use them or to download the original ones.