"Aesthetically pleasing" to one can be horrendously ugly to another. A lot of folks aren't old enough to remember much of the revulsion over the M16 back in the day over its appearance. Whether a rifle chassis, stock, or frame is designed around a clamshell or otherwise, as long as the function, durability, and reliability is accomplished successfully, people's preference can reign supreme. I only find it annoying when someone tries to dictate style and appearance to others in a one-size-style-fits-all manner. Frankly, I think some of the motivation of negative commentary on many bullpups is based on AR entrenchment or even older traditionalism. That's OK. Just leave out the "soapbox" aspect and make it a real discussion.
On clamshell designed stocks...if they are designed to offer true service access without compromising the integrity of the weapon, I think that's awesome. Those of you who are mechanically inclined and tend to perform many home and automotive repairs on your own, how many times have you cussed the designer/engineer of a particular device who assembled that device with no good way to access the necessary serviceable components?...like cars requiring a motor mount to be unbolted so the engine could be tilted a bit to access spark plugs. The RDB appears to offer that nice, easy access to the innards. If the durability and integrity of the gun holds out well, then I'm sure even a few Kel-Tec naysayers might even be impressed.