All I need is to CLEAR it or REMOVE or UNLOAD from that specific frame and not just the option to replace with another, it is very important in my project that it can get back to empty frame
This doesn't make sense. You first say that you don't want to replace it, but then you say you want to go back to an empty frame, which means replacing it with a transparent image.
I think you are confusing "unloading" with "replacing with a smaller image to save memory". They're not exactly the same thing. The System object can unload object images. If instead you want to replace a sprite frame with a different image, another way of doing that without having to use obscure data URL strings, is just to create a small Drawing Canvas object, clear it, and save the image. Then you can load the SavedImageURL in to the Sprite object. This also has the benefit that you could draw any content at all in the Drawing Canvas object (e.g. clearing to a fixed color, adding a border, etc).
So I think there are already a few good options to do exactly what you want. In general it's better to ask "what other options are there?" before "can a new feature be added to do this?"