I think the HD formats are mature enough now to justify support in VLC. From what I understand ffmpeg already supports VC1, and VLC already supports EVOBs that contain MPEG-2 or AVC video, so it wouldn't be difficult to implement EVOB/VC1 support. As for EAC3, I'm not aware of any open source implementation yet, but isn't it mostly just AC3 at a higher bitrate?
E-AC-3 should be done quite quickly (it is included or almost in ffmpeg)
VC1 is almost ok in ffmpeg, and OK in vlc (through dmo if needed)
EVOB/VC1, I don't know yet.