Considering de-facto tempos of considering interesting ideas™ (moreso third-party proposals) in the world of web standards, a year or two ago is far from being old, it is a very, very recent. For example, after 10 years, we still don’t have a way to override a specific background layer without having to respecify all the layers.
Substantively, complicating things usually may make sense after a simpler thing is already accepted, specced, and implemented, but we are far even from that here.
As for aspect ratio (which I believe should be discussed in a separate topic though, as long as discussing anything at WICG makes sense at all), ability to preserve aspect ratio without a necessity to specify an explicit ratio in CSS would be useful on its own:
currently, if an image has both
height specified (to reserve page space for the image so that page jumps once the image has been loaded are prevented), there is no way to preserve original aspect ratio when e.g.
max-width is applied to the image, effectively overriding the original
width while not affecting the original
height. To prevent having disfigured proportions in such situations, we could use something like
aspect-ratio: preserve (or
aspect-ratio: original, or anything else, exact keyword doesn’t matter). But I’m almost sure there will be no such ability for many more years since those responsible are busy working hard on more important things™.