One of the key point when preparing pre-sales content is trying to write and draw what you believe is the best solution in the way your audience expects it. (Of course, you don’t have to follow that rule if your strategy is more like surprising the audience). Whether you should go into a detailed explaination or just throw in key ideas is just a matter of how you feel about the audience from the little you know about them.
When giving our partners a hand with their pre-sales actions (or when we’re driving such action ourself), we more often stick to the “essential-words-only” strategy and produce more drawings than slides. So much so that when it’s time to present our work, we like to stand up and speak. Then our audience is expecting, hence looking and listening.