Thoughts on game design, from a publishers perspective. I've seen a lot of pitches for games that are Forged in the Dark (which, mind you, is incredibly exciting!) and I've noticed a few patterns, primarily around content that is included without first being fully examined. 
This isn't universal, but I want to throw it out there. Have you seen these patterns in your work or in others? What was your approach to address them? My recommendation is just to make sure everything in your game is put there for a reason. Here's the items on my watch list:
1. Genre: Fantasy. If character motivations are essentially "what D&D characters do", i.e. to gain fortune, defeat monsters, fight the setting's enemy, and they aren't contextualized, then likely you're reinforcing colonialist narratives without interrogating them.
What works for D&D doesn't work for your game. Un-examined, it doesn't even work very well for D&D. Ask why the characters are doing what they are doing. If it boils down to plunder, I'd go back to the drawing board.
2. Genre: Urban Fantasy. The trappings of UF settings (like World of Darkness, Dresden Files, etc) are often wrapped in mystery. A secret war, conspiracies, reality warping and all that. These work great for fiction authors because they can unveil their world a bit at a time.
These mysteries work less great for RPGs because it's quite possible that the players make their super cool mysterious characters and then say "what now?" and the GM is also going "oh crap... what now?". Don't get me wrong, Blades leaves a lot of mysteries unsolved.
But what ISN'T a mystery is the action of the game. You're scoundrels who pull off crimes. The closest Blades get to that is if you play a cult. I'd admit the game doesn't tell you exactly what cults do... but then again it gives you 18 possible cult scores on page on page 111!
If you know there's a secret war between two hidden supernatural factions, and the players are going to be part of those factions, make sure it's super clear, what that war actually amounts to and what actions they will take in it. Also, maybe consider maybe not war? (see above)
3. Setting element: Magic and Hacking. If there is any ability that (like magic, or hacking) that can stand in for every other ability with no additional cost, then that ability is both overpowered and boring.
For instance if I can hack a smart gun to eject a clip, hack a cyber-heart to stop beating, and hack a security system to let me enter untraced, then why would I ever do anything else? Magic can fall into the same pitfall.
Attune (in Blades) can do two things off the shelf: open your mind to the ghost field or channel nearby electroplasmic energy through your body. It can do a lot more for those who have special abilities, but otherwise if you want to push it further, you're inviting dangerous...
...consequences, less effect, and potentially ghost or demon tainted outcomes to your success. In general it's about as flexible as any other action, and where it exceeds them, danger lies!
If I'm reading your text, I want to know the roots of that power in the setting, and I think establishing those roots will help not only define the scope of the power, but the likely outcomes (and consequences) of wielding it.
4. Mechanics concern: Bolting on new tech. If you've got a rule for a new kind of action in the game, that is fantastic. If it's core to the game that's even better. The trick is to make the system reflect that, which might make for a deep (and possibly uncomfortable) dive.
If games looks like "Everything Blades has plus a random treasure table" or really "and plus anything" then chances are there is still to many Blades in your Dark! Consider these ideas (and I'd love to hear more):
* Create your system from the fiction you want to see. Decide what you care about (that's really important, this is your game, what YOU care about is what matters here) and build from there.
* Consider your values and how they affect your design choices. They always are!
* Consider your values and how they affect your design choices. They always are!
* Question the narrative of play. Why the are the characters taking the actions they do? What is happening in your setting? How do those interact?
* Leave spaces to fill in the details, but define enough of it that everyone knows the basic parameters they are working with.
* Leave spaces to fill in the details, but define enough of it that everyone knows the basic parameters they are working with.
5. Setting. Make it your own. Leaning on existing IPs (like Shadowrun or Harry Potter or Earthsea) can be a great thrust to get you started, but as you develop, keep developing your setting as well.
By the time it’s out in the public (for playtesting or publication) it should have its own distinct universe, even if that universe is tiny and still growing coming into shape.
Setting can all be generated procedurally by giving the players tools for developing the setting, but they still need A LOT of guidance on this. No game is "every game", nor should it be. The more direction and tools you give players the shorter the on ramp is to play!
