Also, when trying to upscale a sequence already transformed, this vital and confusing setting determines wheter if you are going to spend a weekend correcting scales or not.

Mike's suggestion is a good one.

I'd rather see it more closely match After Effects with the options being Scale to Sequence, Scale to Sequence Width, and Scale to Sequence Height. So, essentially the same thing, but using "Sequence" instead of "Frame".

In the meantime, I'd like to see Scale to Frame Size renamed to "Scale to Frame Size (Scale value remains 100%) and Set to Frame Size renamed "Set to Frame Size (Scale value changes).

I use both of these and would not like to lose one over the other and I'd find it helpful to have what happens plainly stated.

I support the author of the article and it is really necessary to release flexible settings for different aspect ratios. Now it is outdated and does not work as we would like to see without self-correction and fitting media into the sequence frame.

Set to frame size - reduces the frame to the size of the sequence only in proportion to the correct display on the screen. This changes the Scale parameter from 100% to 50%. This option does not cut pixels from the image, allowing you to get a better result if you want to scale this image back to 100%. The image remains in its original quality.
Scale to frame size - reduces the frame in accordance with the size of your sequence, while the Scale value remains unchanged 100%. This means that this parameter cuts out extra pixels from the image, making it from the original resolution in a reduced version. You will not be able to return the image to its original state. This method is used only when there is no need to subsequently enlarge the images for the Zoom effect.

It took me a LOOONG time to learn that "Set to Frame Size" actually means "Scale to Frame Size" and "Scale to Frame Size" is just something weird to be avoided.

Great to hear this is 'Under Review'.

"Scale to Frame Size" is basically only useful when working with proxy files, and then swapping out to full resolution files. With it, we are able to make scale adjustments on clips and adjust the frames how we will want them, and then swap the proxies out with camera raw clips and keep the same framing and scaling.

In my experience, many productions are shooting at higher resolutions than the final video will be rendered in, to allow for zooming in and/or stabilization during editing. It is assumed that we can zoom in (for example up to 200% on a 4k clip in a 2k sequence) without losing image quality.

By rasterizing the image to the resolution of the timeline, it takes away the only use I can think of for "Scale to Frame Size" as a feature. I can not imagine why anyone would use "Scale to Frame Size" as opposed to "Set to Frame Size" with the rasterization happening.

Please change "Scale to Frame Size" so that it keeps the video scale settings the same across multiple resolution source files, but without rasterizing the image to sequence resolution (the way Resolve and Final Cut have done it for years).

"Scale to Frame Size" is basically only useful when working with proxy files, and then swapping out to full resolution files. With it, we are able to make scale adjustments on clips and adjust the frames how we will want them, and then swap the proxies out with camera raw clips and keep the same framing and scaling.

In my experience, many productions are shooting at higher resolutions than the final video will be rendered in, to allow for zooming in and/or stabilization during editing. It is assumed that we can zoom in (for example up to 200% on a 4k clip in a 2k sequence) without losing image quality.

By rasterizing the image to the resolution of the timeline, it takes away the only use I can think of for "Scale to Frame Size" as a feature. I can not imagine why anyone would use "Scale to Frame Size" as opposed to "Set to Frame Size" with the rasterization happening.

Please change "Scale to Frame Size" so that it keeps the video scale settings the same across multiple resolution source files, but without rasterizing the image to sequence resolution (the way Resolve and Final Cut have done it for years).

The Set and Scale to Frame Size options always causes confusion, I've been using Premiere for a number of years and I can never remember which is which. Do we still need both? I only ever use Set to Frame Size. If both are needed could they be renamed to give some clue to what they do.
See:
https://community.adobe.com/t5/premiere-pro/set-to-frame-size-vs-scale-to-frame-size/td-p/9036658?page=1

Agreed! Time to replace some Adobe programmers with AI bots that properly understand English!

The names are backwards from the logic of what they actually do. Set scales smaller or larger and Scale sets it be the resolution of the timeline throwing away the ability to scale with the clips higher resolution.