My own preference is to have it as close as possible to the way it would have looked on opening night in a top cinema. I think both directors and cinematographers are tempted to change the original look - have a look at the several versions of Halloween and The Thing, all supervised by...
The problem is, UHD is almost certainly the final consumer video format we'll ever see. I'm not sure how much of a draw new restorations would be for streaming services.
What about more extreme examples? Like what Friedkin did with the first blu-ray release of The French Connection, or Lucas's endless tinkering with the Star Wars films. Are you okay with those because they were director approved?