Add a way to resize an exported image with Export As method to a specific size, like Save for Web can
In the old "Save for Web" function (please keep it!) it was possible to resize "on the fly" the destination image (EG my file is 8000 px but I can save an exported version of 800 without opening and resizing afterwards)
In the "Export as.." function none of this is possible.
Nicola, Illustrator has several methods of exporting images.
Save for Web deals with one artboard only, therefore it’s possible to specify pixel dimensions for it.
Export As can export chosen artboards at once, but it works in bulk, with resolution coefficient only, and it has no control over dimensions per image. It better fits printing tasks.
Export for Screens is a newer method, designed to bridge these two methods together, — you have control over artboards, and can set specific dimensions. It’s not perfect, but can solve some problems you might have.
Have you tried it? If yes — why do you still prefer using Export As, if it does not have the thing you ask for?