No, I don't like Shakespeare, but he has the disadvantage of using a language that hasn't been used for 400 years.
HH: Do you think these would make a reader stumble?
Your quoting style makes me stumble, I never said that. Although I do agree.
No, you don't have to use the simplest vocabulary every time. It's about your audience and your purpose. In the this case the audience was an ESL student asking a question about common usage. That's why I explained my background. I write content for new students from all over the world about arcane library services and practices. Again, it colours my thinking.
What of those situations where people know what was said but they don't know what was meant?
Well I don't think using a more complex vocabulary will make them a little more wiser.