Mr. Graham doesn't use the term, but purple prose odious to read and I would agree that complicated writing is often used (e.g. in academia) to obfuscate the key message and bolster weak arguments. On the other end of the spectrum too much simplicity is exhausting to read; short, unvaried sentences are boring. For informative writing, I agree that ideas should be clearly and concisely expressed for the intended audience. For this purpose I'd highly recommend "Make it Clear" by Patrick Winston, who was known for his work in AI, but also a lecture series at MIT called "How to Speak".
Which words are deemed "fancy" in the English language requires knowledge of fluent English and jargon of the intended reader. For a native German speaker the word "ersatz" is commonplace, but it probably isn't familiar to many Americans. Likewise, Germans prefer "fancy" passive constructions--sentences that feel inelegant to English speakers, sound fine to Germans.