There is no difference between RPing in this game vs any of game out there. RPing ALWAYS comes down to the imagination of the player. It is like then pen and paper dungeon and dragons. You aren't really doing anything other then keeping a list of stats, you are only given the tools to RP. You have to then use your brain to do the rest. This is no different then Skyrim, no different then the Witcher, no different then Dragon Age. In fact it is EASIER to RP in Skyrim because of it openess vs the Witcher or Dragon Age which, I am sorry many will disagree, are action adventure games where you play the story of a character not a true RPG where you define your role. Dragon Age is more RPG then the Witcher but still both are Action Adventure games.
Skyrim gives us the tools to RP, and it is by far the best game out there for RPing. If you can't use your brain to RP, then that is your fault. You are expecting a hand written story where you just follow along and feel like that is who you are, and if that is what you want go play Mass Effect or The Witcher 2. This isn't a rail-road, theme park game. It is a open world where you are only limited by your imagination. Sadly it seems many people are so lazy these days they can't muster up the strength to do that.
Perfect example. I roleplayed a Imperial merchant who never raised a weapon in combat. It took a lot of imagination to make it work, but I had a blast doing it and it was the most unique experience I have ever had in a fantasy game. That I explored and adventured in this world as a lowly merchant who was weak and had no physical prowess.
I disagree with you in some notes. First Dragon age and Witcher are not action adventyures, but thats an argument for another day (to be fair i haven't played witcher 2 yet. The problem with roleplaying in skyrim is the type of game it is.
Dragon Age (origins at least) - is a Action Tactical game where you define your chracter (roleplay) through dialogue, not actions, because most actions/quests you'll do on everyplay through
Witcher 1 (and 2 if its similar) is a Action Roleplaying game that plays like a choose your own story book. The character is defined and well created. His personaility is always the same almost, but you get to choose how the story plays out. Similar to Hawke in DA2 and Shepard in Mass Effect
Skyrim is a Roleplaying game, where you define your character (roleplaying) through action not dialogue. The quests you choose to do, and the skills you use, define your character. Thats what i believe many people in this thread are trying to say. If Skyrim let you define your character also by your dialogue choices, i think many people would be happy. Defining a character through action is great, but unfortunately the way everything was scripted, it doesn't affect the gameworld as it should, also NPCs dont react accordingly.
This is the issue i think