Weapon: I hope they bring back the spear/crossbow/throwing darts as these were all very creative and added much variety to how you could go about adventuring and altering your character.
Magic: For magic I hope they include jump/levitation/slowfall spells back into the game! These added so many interesting ways to get around and forced you to be much more prepared than just carrying health potions everywhere.
Realism: Maybe for this having a hardcoe mode option like in Fallout: New Vegas! Letting us choose how intense of a roll playing experience we want to play with. I also read a thread about armor damaging where our and the enemies armor would show wear and tear as we fought through dungeons showing us how damaged we really are as well as adding another notch to realistic effects! Making footprints in the dirt/snow you walk in would be nice to that effect too.
Morrowind had so much more variety than Oblivion! Not saying that the game was not great because by all means Oblivion and Morrowind both are some of the funnest games ever created. But I personally enjoyed the freedom and variety of choice that Morrowind aloud me to Opt. for in game while using a much larger variety of skills to accomplish tasks.
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On a side note, I also pray that this game is Single Player only! The only online option I would appreciate in a Elder Scrolls game is Online Arena fighting against other players to test your true skill in combat under a variety of circumstances.