Brompton have always been glacial in the pace of product development. They will not change a thing unless it demonstrably improves the bike. It took years and years of nagging by dealers before they began offering anything more than black/red paint. So good luck persuading them to fit a kickstand bracket any time in the next decade.
You're not the first person to imagine a better Brompton. If you really think there's a great untapped market for a Brompton kick-stand bracket why not go ahead and design it, manufacturer it and bring it to market? There are plenty of folks offering Brompton hop-up parts.
Yup, Brompton hop-up parts are a dime-a-dozen so to speak. Most of them are just that...while they may exceptionally well-crafted, they aren't necessarily exceptionally well integrated into the function and DNA of the product they are intended for.
I must be naive, because I find many aftermarket parts are almost always a compromise in quality, compatibility, functionality or any combination of the same. This isn't just applying to Brompton aftermarket goodies....I've had the same experience for years on Vespa and other motorcycle aftermarket stuff, as well as items for many of the automobiles I've owned over the years. Hence my
shout-out hereto the actual MANUFACTURER.
While they may be glacial in their pace to refine their products, when they do it's typically done as well as it's going to be done, works in concert with(or improves upon) the rest of the functions of the machine and with the full attention to their product's entire reputation in mind (most aftermarket suppliers don't take that X-factor into account). Again, this doesnt just apply to Brompton.
As an example: Leatherman, an American manufacturer of multi-tools, has actually produced new products based on many modifications posted on forums by those who own, love and have modified them. Clearly they have an ear to the tracks in terms of what (else) their client base wants, and then act upon it.