At first glance, the painterly world and the HUD would be as distinctive as something you'd see in Planescape: Torment. We'd need to nail down a new art style, but there's elements related to Planescape that transcend that universe (dimension-bending landscapes, Escher-layouts, etc.). We wouldn't do anything approaching traditional fantasy in the look/layout of the world. Why? Because I'm exhausted with that. And if that's not compelling for people, then they won't back it on Kickstarter, my question of how appealing that is would be laid to rest, and I'll never have to wonder about it again.
A camera and click-movement presentation similar to the Infinity engine isometric games. Even if the mechanics are different, at first glance, the game should share the view that Planescape did.
Having a character basis and an advancement scheme with spells, traits, and abilities that are suited to the campaign setting and the system and narrative mechanics. As an example, Dak'kon's Unbroken Circle of Zerthimon and the spells he gained from that had a strong narrative bent, and I enjoy balancing out skill and spell trees that reinforce the philosophy of the world.