I know my opinion is generally not welcome around these parts but I'll chime in nonetheless since you guys mentioned "linearity".
No... linear is a straight path, one path. Non linear is not... Just like the definition of rpg, people have created their own definition of things related to gaming and it's just plain wrong.
You really like telling people they're wrong. Linearity does not just mean
a line, not in engineering, not in math, not in science and (because of that) not in gaming.
A particle system is not linear if each element's behavior can be drawn as a line, but rather if it satisfies the properties of linearity. Summarizing, a linear system is one such that f(Ax) = xf(A) and f(a + b) = f(a) + f(b). This means factors may be extracted and applied later (1) and it can be separated into parts (2) with either operation leading to the
exact, same results. A linear game is not just one where you follow a predefined
line (like, yes, many FPS's) but one where factorization and separation have no effect whatsoever in the game world or game state. Many "open world" games of this sort are simply a bunch of "little lines" that you traverse one at a time if you will, each of them contributing just as much as they would to the world otherwise, if you had done them in any different order. Performing one task before another doesn't change anything, and of course there is no compromise. Rarely will you be confronted with the requirement to choose either one or another. Also, in how many ways can you
actually complete missions in such games? Can you, for instance, change the terms for quest completion completely if you happen to find new information? Are you taken to places/people/scenarios that are completely dependant on your actual choices, and wouldn't have been there otherwise?
I understand the way you play Skyrim and I think it is cool. You make your own story in a virtual world and have a great time. Nothing wrong with that. But Skyrim is essentially f(a + b + ... + z) = f(a) + f(b) + ... f(z) where you happen to choose a subset of missions that match your current character. The game does not respond however, you cannot reach a unique state describing or encompassing all you've done. But this is alright because clearly the goal of TES games is not to be cRPG's, but to be sandboxes to "live another life, in another world".
Just please understand why we say it is linear, and largely static. Compare that with cRPG's and even decision-heavy games like The Witcher 2, where the game gives you opportunities based on what you did before. These actual gameplay elements wouldn't be there otherwise, there would be something else or nothing at all. Not just in terms of locations, but in terms of world states.
Edit: Just wanted to add that we are commenting on the actual
video game, the product that Bethesda developed, published and sells. The game YOU personally get out is dependent on your expectations and your style, you make the RPG with your personal approach using the video game as a tool. Choosing to avoid certain tasks because they do not match your character is fine but that is part of the game YOU create, where game, story and characters are in your head. The game Bethesda made is one where everything goes and your actions do not matter. It is a sandbox, that's what they do. We might as well approach GTA with these same standards and "role play" the hell out of it.