I must confess this random book feature is a function I would never use - why would I want to have it choose for me what ends up being book 3 in a trilogy for instance?
Your suggestion of a "random series" sounds a bit more "practical". To each their own of course and loads of stuff I have created as plugins that others will have no use for. My backlog is too immense with so many "high priority" ones to read to let randomness decide my reading order
