Markdown is better for many people that want quick formatting even if you have to remember the syntax. Dumbdown is for people that want easy formatting, even if it takes more keystrokes.
They can just use a word processor then. I am not really seeing the target audience for this.
Easy? Markdown was based on people already using "" for bulleted lists, /slashes/ for italics and bold* in plaintext email.
People were writing valid Markdown before it was invented. It doesn't easier than that.