I checked several sources for this story. The liberal ones claim that Bush and Obama were equally elementary in the speeches and today no one would be able to understand the complex speech and references of the pre-1920 politicians. But others say Bush's speeches were better. Actually, it's the speech writers, with the politician putting in his own touch. I find Obama's mannerisms, teleprompter dependence and stammering very distracting, as were Bush's facial quirks and folksy good ol' boy mannerisms. But Bush was an avid reader of history, biography and politics--Obama depends on hip hop music on his I-pod and it showed.
I took a writing class a few years ago at Lakeside in which the instructor told us the most difficult vocabulary and complex constructions were on the sports page of the newspaper. I was once a speech writer for an Ohio female politician. It's not that hard to learn the cadence and style of a speaker by reviewing previous speeches. But you do need to consider the audience. Speaking to a conference of state workers was different than speaking to a gathering of unemployed workers who were over 55 (the area I was working in).