I don't see much that's terribly wrong with the design, aside from the hollowed-put index pips. The indices should be the most easily-read part of any playing card because they're the most commonly used identifier when playing cards. Making them as outlines makes them stand out a lot less.
Beyond that, it's a rather minimal design without actually being minimalist. It contains most of the traditional design elements in the standard manner, with the exceptions of a few pips on selected spot cards and the court cards - typically the most interesting part of a deck aside from the Ace of Spades and the jokers. I can see where the simple, geometric back design would appeal to a cardist, but I tend to think that most people would consider them a little bland.
Mind you, that's just my opinion, and I do wish you good luck with your deck. Again, there's no real elements that would be considered design flaws other than the part about the index pips, and even that is a matter of opinion to many. I'm probably a little biased against the design because there was an onslaught of minimalist designs a few years ago, some better than others, that were sprouting all over Kickstarter like weeds. To me, the theme's a little played out. But you never know - perhaps enough time has passed that the market feels ready for another deck in the same vein, one that's a little less than fully minimalist in its design.
I'd rather see a designer go out there and try something new, different and interesting than see the same old deck over and over again - even if it's a design that's not necessarily my cup of tea. It's a sign of a vibrant marketplace for the art of playing card design and at any given time there's plenty of decks out there that appeal to me, more than I can typically afford, so as long as I actually have to be choosy about what I purchase because the selection's that good, I have no worries! Just because it doesn't appeal to me, doesn't mean there isn't a niche for it out there among the card-buying public - you just have to find that niche.