I have the same question. I would consider purchasing the author’s Premium Slider to get random order, but I see no mention it in the documentation, and there appears to be no way to contact him at http://www.premiumslider.matthewruddy.com/ or anywhere else.
As it says on the website, you can contact me via [email protected] if you ever need assistance, especially with the Premium Slider.
Random order current isn’t a feature and I would hope to add it in future, but the Easing Slider is going through a major redesign I’ve been working on for half a year now slowly so it most likely will be included with that.