Way-to-early findings.

Most people will make a Custom Character for their PC. A minority of those will pick up the Dark Urge Backstory tag.

The most popular party members seem to be Shadowheart, Karlach and Gale.

The least popular is currently Minthara, despite all the naughtiness she offered in EA. I presume this has a reasonable lot to do with her being (probably) accessible only on a playthrough where you'll embrace the power of the tadpole and possibly join the cult of the Absolute. But most players will go for a "good" playthrough at first.

For the romances, people seem more interested in Karlach and Shadowheart. Jaheira currently beats Halsin and Minthara, which I wasn't expecting. I did cast a vote for her, so I understand/agree, I just wasn't expecting she would have something resembling a broad appeal. Bear in mind that this is based on way too little data, at the moment, to be significative.

Flash info : The Dark Urge is not an Origin Character. And it's not a new concept.