OnePiece

There's no way they would be able to get the voice actors to voice the whole thing all over again.

I'm doubtful they'll even manage a complete production of the whole thing. Re-doing the voice acting of a series is hardly a hurdle in the grand scheme of things.

And ball-and-chaining themselves to Toeis original version by re-using the original audio track of each episode defeats the point of doing a remake.

It would leave a lot less leeway for addressing the production issues Toei ran into over the years.

Now, if the audio assets are all still available as individual original recordings, that'd be completely different.