also, how many times do I have to tell you, mokram, don't put stuff in the "title" part of your post
anyway,
(vote in red)
a) We've been doing VR helmets forever and they have yet to catch on, so I don't think so.
This seems to me to be the most attractive out of what you've given for possible "future technology". Like someone said, using more of the articulation that the human hand has could make for some pretty awesome control. I'd worry about the accuracy of such a controller, but it could be really cool.
c) Nope. Waaaay too much effort. I can see it for maybe a few webcam kind of games, maybe, but not on any kind of large scale. Besides, this idea has also been around for ages and has yet to "catch on".
d) Honestly, I still see this as the most likely thing to happen for a good while yet. I can imagine VR becoming the way to do it in the (far) future, but people have been wanting to do VR for like thirty years and it still hasn't happened without being expensive, ridiculous, or both.