Aye I am very much looking forward to Witcher 3. I never got into the first two as I felt they were too limited and … well some other reasons which I will refrain from getting into since it sparks to much controversy
But W3 sounds like a great mix of story and sandbox and even if "my" character will be defined for me at least I will be able to do a lot of exploring.
Don't get me wrong, as I tried to point out, I enjoy those games as well - Mass Effect was loads of fun but .. well I played it more like an interactive movie and I never felt like I was playing my character, I was just playing Shepherd.
Also I was being a bit flip on the RP comment (sorry I was reacting to the no story no gameplay comment) because I know everyone has their own definition (although I have studied it, I wrote a 50 page research paper on the topic of role playing in games for a seminar class on personality). For myself I see three very rough levels of RP. One is the psychological version. You role play your dominant mother, the kid you bullied, a male coworker, whatever … in that case you try to get into a role outside of yourself to see what it is like.
Another is to play a character in a game for fun and exploration. The battle-hardened elf priest, the paranoid halfling, a different gender or alignment. the last one is when you play as yourself but with a twist - which is how I play 95% of my games. It is really just a subset of the second.
For example *if* I were to be reborn in X game world as Y how would I be? For example I tend to be a vegetarian, non-aggressive, and more mental focused person in real life. In Skyrim I play a powerful and dangerous werewolf mercenary. Now I am still there inside … he is a hero who does good and fights the dark side of the beast (just like we all have our shadows). But I am certainly more violent and physical in the game. I am playing a new role because the world demands it to some degree.
Anyhow I wish to avoid another RP argument so just trying to explain my view on how I do it. I have a very vivid and strong imagination - always have. I find it easy to escape into these sandbox games and create all the context I need in my head. All the NPCs get deeper personalities that I build around the skeleton outline provided by the developers.
Think of it like a play - props in a play are minimal and just meant to frame things. Me and my character then flesh it out. Of course modding can help a lot as it lets you really adjust things a lot more.
Granted the more the world reacts to things your character does the nicer it is as you get feedback on what you are doing - one reason I liked DAO more then DA2 - but lets face it no matter how good the game it will never equal human AI and interaction. So I use my mind to fill in all the other things, based on the rules, lore, logic, and whatever context the game has provided.
For me a marriage of FNV + DAO + SKYRIM would be pretty ideal
Back on topic - speaking of Daedric planes the one I would love to visit would be Hircines Hunting Grounds. All the woods, enchanted forest, animals, were beasts … the wild hunt … sounds cool (course W3 will have a wild hunt so that is appealing).
EDIT: Also if you have seen my posts in the skyrim screenshot thread (I know, I took that thread over) you can see I also write a lot - I create elaborate stories around my character and the NPC's in the game. All of this adds to the RP factor for me and gives depth and meaning to the game. I also play by fairly strict self-imposed rules that help maintain immersion and believability within the logic of the game world.