Can't drop synchronized text+audio

[rdeltour]

I disagree with the following conclusion:

let's drop Media Overlays spec for now.

Synchronized text+audio is very important for accessibility of digital publications, as seen by the popularity of DAISY standards and now EPUB+MO in the print-disabled community.

The argument, "support across rendering engines is in very bad shape", can be made for many other features (including non-EPUB-specific Web technologies). But there are some RS which do support EPUB+MO fairly well, and there is definitely a legitimate use case.
I believe we can't just drop this use case without providing an alternative solution.

[therealglazou]

Why not. What would be the best way to keep MO there, in your opinion? Still metadata?