Convert text to "preview view" as you type?

Thanks. Looks like this topic has been addressed in an extended discussion already, and looks like there is no plan to add this functionality.

For my use case, at least, it’s really the bold and italic functionality I would care about: So that when a use hits bold on some text, it actually makes the text appear bold, instead of showing just the asterisks.

Is this in fact an exceptionally difficult feature to implement?