This is honestly one of the stupidest kitting choices I've ever seen someone willfully make in this hobby. I hope you reconsider for the sake of your buyers, there is zero reason to utilize concave bars over convex bars. And doing so after your community expressed support for the change just shows that you don't actually care what they think.
40% of my buyers didn't want convex, so there is a reason to keep them concave. Even if more people wanted to change to convex (myself included) I'm not gonna change a product after GB if almost half the buyers don't want that.
I have no idea how you can extrapolate from that that I don't care about what they think, but you do you.
You didn't poll your buyers, you polled via a publicly posted google form linked on Geekhack. Unless you emailed everybody that ordered the set, you did not poll your buyers.
You then ignored the majority of responders.
You're acting like it's a noble thing you're doing by not changing the advertised product but it's literally an upgrade with no drawbacks. Concave bars have never been a feature, they have always been a compromise borne of minibars being a recent development in the hobby, and for a long time it was easier to just use existing blanks for other keys, like shifts, rather than develop actual spacebar molds. I am willing to bet that the 40% of people voting against it is a mix of:
1) people who do not know or understand the difference between concave and convex spacebars
2) people who have an irrational fear that the change would increase production lead times
3) people who did not even buy the set voting for ****s and giggles
You, as the designer, are responsible for making informed decisions on behalf of your customers. Kitting feedback is good but ultimately it is on you to make the best choices given the information available. You made a choice that only stands to hurt customers because of some unproven notion that people really want concave bars. I only stress all these points because I do not want future set designers to use this as precedent and use concave bars thinking they're doing something right.