I think the OPs main point, which is getting buried by the ER 'noise', is that calling a single-bed room an upgrade to a twin-bed is quite a stretch.

If the properties are free to nominate the levels of 'quality' then they could say 'flock wallpaper is an upgrade over plain, so yes your smaller room with flock is considered by us to be your upgrade'.

It'd be nice if they had some clear ground between the benefits of what is offered within the prperty. Not just a minor price point ($10?) that is buying a slightly better view out of the window, or maybe a microwave - which is not an upgrade if it is of no use. An upgrade to ER is an obvious example of 'better' to me, but there are other steps on the way.

I can see that there might still be edge cases where one thing about the offered room is clearly better, but another is subjectively worse. For example I have declined upgrades in the past because they were a newer, larger room but only had a shower: no tub for soaking in. I personally think that any full-service room designed and setup without a tub is a mistake on the part of the property. I don't expect them at an Ibis, but at a modern Hilton in the UK I do. Others would have been delighted with the room.