The deinterlaced, progressive transcodes of 1080i content do not look good in my opinion.
I would like to have the option of configuring the transcoder to generate interlaced output if the source was also interlaced, allowing the deinterlacing to happen on the client.
This could be done in a backward-compatible way that defaulted to delivering only progressive output. As with the surround sound option, it could only be enabled at the user’s discretion, and with a warning that it might not work with all clients.