Poor writers often express mundane ideas with elaborate syntax and esoteric vocabulary.
Setup Claims
Poor writers often try to make up for their boring ideas with complicated sentence structure and vocabulary.
Inattentive readers might be fooled and impressed, while not really understanding the writing.
Alert readers will easily see through the charade and realize the bad writer is covering up for lack of substance with fancy language.
Conclusion (Thus)
A good principle for writers would be ....
Evaluate / Goal
We need a safely worded takeaway that synthesizes these two sentences.
We've been warned about a certain style of writing, in which we're not saying anything interesting, we're just trying to write in a complicated way so that we sound smart.
We might be able to fool some people with this style, but alert readers will see we're being a chump.
So a good principle for writers could be ... ?