I want official Scratch to actually compile projects to JS when not being edited YES.
Since compilation to JS makes live editing impossible to take effect, compilation should be disabled from moment the project is being seen inside, and enabled again when not in the editor. This rule may still be triggered a bit later than it's supposed to be because when the project is still running, going from JS to JSON and vice-versa doesn't seem to be possible to implement. So it should show a warning The compiler cannot be toggled while the project is running.

I wouldn't recommend ST to officially let projects edit their own fps nor let scratchers edit the traditional 30fps to anything else, this could be too easy to get abused. Instead there should be presets : 10, 25, 30, 45, 50 and 60 fps. This option should not be directly visible, so the youngest of this community don't get confused. If a device can't render the specified amount of fps, frame jumping is used to adapt the maximum framerate supported on that device.
All projects are left at 30 fps by default of course, so old projects don't break if this gets implemented.

Everyone who are viewing a project should be able to enable interpolation from the project page using a dedicated button, so both PC and mobile users can toggle it without having to see inside and disable the cloud feature if the project uses cloud variables. Again this should not be directly visible too.