+1 making diversity a goal.
I'm not well-researched on how to achieve it, so looking to you folks for input. The two options I know of are:
* "blind" proposals
* no proposals, organizers seek all speakers
My only prior experience running a conference was "Boston I/O":
http://boston.io/schedule. The year prior, it had a different name, "Developers, Developers, Developers, Developers."
Both years, I set the speaking topics I thought would be good, then found speakers for each topic, trying to find faces that would make everyone in the audience feel comfortable. No call for proposals, turned down a number of people who asked to speak, was very heavy-handed and top-down.
I really don't know if that's appropriate or not, but the result seemed to be pretty good (something like 35% female attendance, for instance). Everyone seemed comfortable and felt welcome.
I'm sure there is actual research done on this kind of thing that is more worth following than my anecdote, but wanted to share the "no proposals" / authoritarian style as an option to consider.