Provided the binding posts are made mostly out of a high quality, high conductivity metal as opposed to the mostly brass ones that sell for a few bucks, the damage they cause should be fairly minimal, and for most people being able to change cables or use whatever cable length they may require is worth the small sacrifice in sound. Using the same speaker cable both externally and internally I think will provide better results than eliminating binding posts, or at the very least using same metal cables, ie if Omegas are wired internally with solid core copper, use solid core copper speaker cables. Whatever you do, don't use silver plated copper anything.
In spite of what Nordost and other companies that sell plated cables may tell you, plating one metal over another for cables that operate in the audio band (rather than S/Pdif cables, USB cables, and other UHF types) is pretty much the worst thing you can do, sound wise.