I thought I read someplace the BD Audio format could play without video as does SACD. If that is the case that leaves DVD-A which might have to be sacrificed for an audio only player. I don't want to start a big discussion between the supporters of SACD and DVD-A but it would be amazing to have the SE's Sabre 32 DACs (or?) and lossless audio! I think I could live without DVD-A in a player to have a piece of gear that would slay the CD market as oppo has done with DVD/BluRay and have BluRay Audio. If DVD-A was absolutely necessary the player could have a basic video section and a composite out so the DVD-A menus could be displayed.
BD's can be authored as audio only and there was even a concept for it in the format spec (Profile 3 is for audio-only), but it has not been picked up by anyone - at this point, there is no established format for audio-only BD. Most music BD's have some video component, at least for navigation, and many at this point are concert discs that include video. If you exclude video, there will always be a bunch of discs that are hard (or impossible) to use. You also will make it a lot harder to set up the player without an on-screen menu, as these players are complicated.
The biggest problem is likely one of market. If they build an "SE" player but skimp on the video section, then they are marketing it solely to the "audio player" market - they are alone with a relatively costly player that has a good analog section (less and less often used in home theater setups) and a merely average video section. That would limit them a lot more than if they have a good video section, as
that player would be able to complete with more expensive products from Denon, Marantz, Pioneer Elite, and the like. If they were a bigger company, they might be able to justify building a "BDA-95" that had a no-holds-barred analog side and just enough video to allow a setup menu and on-screen display for disc playback. As it stands, though, that's probably impractical.