It's a niche product that started out on kickstarter. They don't have bottomless pockets, neither do consumers, and these toys are already out of reach for 99% of the world to begin with (price vs function vs necessity). Yes it would be nice to have all sorts of things, but your wishes as a consumer and their reality as a product/service provider are two different things with some overlap.
I'm sure that there are many products, enhancements, accessories, etc that FM would love to put into production, but they have to prioritize, make the best choices given their resources, and release product as they are able to do so.
I can't imagine the amount of extra cost involved in testing and certifying their products in additional configurations to the point where they can confidently provide warranty for all of those additional configurations (eg. longer rails). I have no idea how that fits with their current profits and R&D budget. The easiest argument is that there wouldn't be much harm in producing other rail colour options and assembling based on colour choice. That said, I'd guess that it's far easier and less expensive to create and store acrylic rail guards of various colours that might or might not sell well than to produce and store metal frames that might or might not sell well. It also gives consumers the ability to change the look of the OW whenever they please; I've made small changes to mine a few times, already.
The XR is a phenomenal product. Sure, there are things that would have been great to have, but by no means do I fault them for the the products that they've put to market or how they've done it (other than the lack of proper communication regarding delays for the people who purchased the Pint (I wasn't one of them)). With limited resources and a limited market you can't expect limitless options.
They've provided this "Product Wishlist" section to say "We are listening and open to ideas." I have no doubt that they want to provide a great product to consumers because that's what will drive sales and keep them in business, but they don't "owe" anything to anyone. At the end of the day they can only do what they can afford to do and will do what makes the most business sense given the information that they have (and we don't).