In the Classic Map Viewer the Zoom to Layer function zoomed in to the visible scale of that layer. In the new Map Viewer that has been changed to zooming in to the full extent of the layer.
In my view the zoom to visible scale would be much more useful, but I don't want to deny the usefulness of the zoom to full extent function, so I propose to add the zoom to visible scale function. Preferably it should zoom in to the center of the current map extent, not to the center of the layer, like it does in the Map Viewer Classic.
(Another idea would be to let the function depend on whether the layer is currently in its visible scale range or not. So Zoom to Full Extent when it's visible, and Zoom to visible scale when it's not. Any comment? Maybe I should post that as a separate idea.)