You keep saying Skyrim has linear questing, I wonder; how is Skyrim linear? You can literally approach any quest whenever you want from whatever angle you want and a lot of quests can be finished in several different ways. The entire game is open-world and the only thing in Skyrim that I can think of that is somewhat linear are the dungeon (I'd take a Zelda dungeon over a Skyrim dungeon any time any day of the week).
And setting does not define whether your game is an RPG or not. Mechanics and whether the game allows you to actually roleplay a character is what defines an RPG. Setting has nothing to do with it.
I'm just saying there are limitations in every genre. Even the presumably unlimited world of D&D (Pen and Paper) was constrained by all kinds of things. Could I go up and punch the Lady of Pain in the face and expect to live? No. Heck, could I even find the Lady of Pain to punch her? No. Could I cast fireballs at level 1? No. Could I teleport myself across the entire universe with no special item and just because I feel like it? No. Could I multi-class to a rogue not as a human without the EXP penalty? No. D&D was arguably more constrained and limited than Skyrim.
There's a reason genuinely pure roleplaying experiences (Second Life, etc) aren't as popular, and that's because they offer literally nothing on the part of the creator. You can be anything and go virtually anywhere in Second Life, people are as fascinated by the limitations as the freedoms.
I'm probably beating up too hard on this though, if you just want to say Skyrim offers the ability to play any class and design your own character and travel a wider span of land in some ways than your typical Tales game which gives you a specific hero and all that, fine, but I'm way more interested in the similarities rather than the differences between the two genres.
That's why for instance Xenoblade Chronicles X gives you the ability to design your own character male/female etc (a first for the Xeno series). I'm not entirely sure that's a good thing personally but the point is they spill over all the time.