Blessings are a subject that is not well known. Many people think that the order of blessings established by the Kneset Hagedola [Men of the Great Assembly] means the actual language of the blessings. But the Gemara in Brachot makes it clear that that is not the case. What they established was whether whether you have a structure where there is a "Blessed art thou " in the beginning and end or only in the beginning. So for example the blessing after a meal of bread. What was established was that the first blessing starts with "Blessed are Thou" and ends after a middle area with another "Blessed art thou."
This is obvious in many places in Brachot and Tosphot. But one example I thought to bring to show this point is in one of the earliest sidurim of the time of the Geonim where the first blessing before the Shema in the morning is the first short sentence. Then another short statement. And then the final, "Blessed art Thou who makes the lights".
So while it is true that this blessing and many others were expanded, still the actual obligation is very short and simple. [The knowledge of what is obligatory and what is optional would make the morning prayer shorter.]
