Well, it doesn't have people on horses, but IMO it's less original than the art for Brandon's later books.
Perhaps a parody cover series with people doing everything on horses is in order. Warriors on horseback mounted around a table sipping tea. A magician on horseback raising his staff to the heavens... to knock a book he needs off the annoyingly high shelf of his bookcase. A military rank of horses rearing as one, riders dumped off the back optional.
Wide-angle shots on covers do very little to sell me on a book. Yes, most fantasy worlds have buildings, cities, trees, and people who do things that are interesting to one degree or another. You don't need to show me what's the same. Show what's different about the novel on the cover. If you have magical zombies, show the magical zombies, not a shot of a lady looking at a (admittedly very fancy) city and a dude looking at her.
I love the original Mistborn covers when it comes to originality, but the mass market covers are just so much more accurate to the story that I prefer them overall (despite the pose-y nature of the shots).