There's plenty of games that have stats that are not RPGs, there are no RPGs that do not have stats. Stats are a constant. And in the games that do have stats that are not RPGs, what do those stats represent? The always represent difference, or progression. So stats are a constant and are one defining aspect of an RPG. Therefore you could say stats are part of what makes an RPG. So theres nothing wrong with my first statement. So really, other games that have stats is irrelevant, since without stats in some way, your not playing an RPG. Hence the term "stats make an RPG".
Saying that stats make an RPG implies that stats define an RPG. At least, most people would infer that that is what it implies. What you are saying, apparently, is that stats are an inseparable component of an RPG. It may be that stats are an inseparable component of an RPG, but they are not enough to identify a game as an RPG. At best, as I think you would agree, you can recognize a game as a non-RPG by its lack of stats. However, stats cannot be used to distinguish a non-RPG from an RPG when both games incorporate stats.
In Magician Lord and in Street Fighter 2, your characters have a health stat that functions the same as the health stat in any RPG. Your characters also have damage stats representing their power, although these stats are displayed only indirectly by the harm you inflict on your opponents' health. In Age of Wonders, all units, including your leader and your heroes, have the following stats: Attack, Defense, Damage, Resistance, Hits, and Movement. Those stats represent difference or progression no more than RPG stats represent difference or progression. They are a unit's attributes and reflect a unit's abilities.
The OP is talking about identifying Skyrim as an AA, as an RPG, or as some hybrid AA/RPG. If constant stats make a game an RPG, then any game with constant stats would be an RPG. As can be seen with Magician Lord, Street Fighter 2, and Age of Wonders, having constant stats does not make a game an RPG. Therefore, Skyrim having constant stats doesn't make it an RPG.