If you have the latest firmware installed, you already have gapless and support for FLAC and Ogg Vorbis (no Opus or Speex unfortunately, but would be great to have).
I agree that having support for higher-capacity uSD cards and a more standard USB port (though I’d prefer USB Type-C) would be great, but I’m a little confused on what bluetooth support would be used for.
I’d love for Sandisk to remake the Fuze, but I’m not hopeful… :mansad: