First off, I want to say this keyset looks amazing. I have read most of the suggestions both on GH and Reddit; they're all great.
It seems as the keyset is still in the Pre-IC phase, so I wanted to add some ideas. Bare with me, I have a lot of ideas, and they might just be small nit-picky things but here are my ideas:
1. The gradient is stunning. I like the addition of the Purples, Pinks, and Blues. Please keep the gradient spacebar: BEAUTIFUL!
2. I think most of the novelty keys have too much going on. The images are really cool, but they take up too much of the key face and have too many colors. To combat this, you could make the images a little smaller to fit the key face. I think you could just make the image one color (Example: The Earth novelty that replaces the 'Home' key could just be pink on black)
3. I noticed the blank gradient keys for a 65% layout. It would be interesting to see all 8 colors but all Row 1 for the function row. You could even incorporate a design like a simple star on it
4. The numpad hasn't been mentioned much, but you were thinking to do a gradient numpad, right? If so, I think you should have an alternate numpad kit that is just a "Mono Numpad" and a "Gradient Numpad"
5. I think it would be a great idea to have lots of kit choices. It reminds me of KAT Iron; they really wanted to cater to everyone's taste. They had gradient alphas/mods/numpads and also had mono alphas/mods/numpads. This catered to both audiences: bold keebers and minimalists. My take on this would have the mono kits use the purple keycap with the light blue legends.
6. A "Don't Panic" key would be really cool, maybe on the enter key (props to the reply above)
7. I like the clever words used to replace alt/ctrl/shift. Keep those ideas!
8. Keep the "F-12" or "E-12" function row legends. It's a clever but subtle take on the function row
Some points others have mentioned:
9. The ZSE4 keys (Purple on Gray) could be kind of hard to read
10. Modifier legends have an awkward font that doesn't really match the alpha keys. You could potentially try a more blocky font that follows a cyberpunk theme
I know that was a lot of ideas, so take them with a grain of salt. Other than that, I really want this set to happen, thanks for reading, and keeb on!