There should be new range weaponry, such as crossbows and heavy crossbows.
Also new melee weapons; like swords, spears, war hammers, flails, greatswords, etc etc.
able to enchant your own arrows, bolts, and weapons.
There should be new races that relate to either vampires, werewolves, or dragon kin
There should be new magic arts; such as wind magic that you are able to continue the winds around you and maybe cast a tornado that can whip your foes around, necromancy that you are able to summon more than the undead, make illegal potions, and able to create poison spells, and blood magic, which ables you to counter back at your foe unexpectedly with great power. (Do not worry; blood magic existed way way long ago, so you won't be copy writing off of Dragon Age.)
There should be also a new effect to your character if he/she has been critically damage; such as bleed outs, which would be extremely useful for blood magic due to the fact that blood magic can be used either on another life form or your own blood line if bleeding out.
There should be realistic gore, like the parts from the fallout series to where you either blow someones arm off or head off; except in the Elder Scrolls, you are able to lop their arm or head off if you used a sword, see blood gushing brains splattered on the pavement from a blunt weapon such as war hammers, or see your victim turn to ash if you used a fireball on them. as i said, realistic. or at least add these effects if the hit becomes a critical.
While the character dies, the bleed outs should continue. no vanishing blood like from oblivion. this is a M rated game, not a rated E.
There should be dragons in this game, and maybe some advanced technology.
Bring back most of the stuff from morrowwind; like levitation spells and other activities that were pulled out of oblivion.
Many friends of mine told me this game should be MMO; personally, i don't see this game being a MMO. Less you developers are able to make a great main story line with a massive map out and able to fit in MMO, i recommend not to do that at all.
There should be at least prosttutes in the game; i know that during the midevil times, prostitution was very well known and popular, but hidden. Also able to have six (realistic.)
Also able to raise a family.
Respawns are always a loving joy of the game. Like you kill a group of bandits and a week later they are back to their original places; just like in oblivion.
Better caves, dungeons, and forts. Less undead, more humans and animals. maybe add in factions between tribes, like from fallout new vegas to where consequences are severe if you side with one side against the other.
There should be karma in this game. like if you do something good, you become good. but if you murder a innocent civilian, you lost karma out of it. so basically like from the fallout series.
Have followers (companions) in the game; whether its a main follower or a follower you can hire or a follower that has full attention and trust in you after accomplishing the guilds story.
Any downloadable content that is made should be copied to CD's and sold to stores just like on fallout 3, cause some consumers does not have xbox live and is not able to achieve those extra features that you have made.
You should have a base of your own and still able to buy houses.
There should be more villages; maybe add a kingdom or two in the game.
The combat system should be a little more realistic.
Lastly, able to marry on the game and maybe raise a family.
These are most of the idea's i have thought of. Some may like it, and others may disagree on what i think. but whatever works is necessary. I mean really, it doesn't hurt to express your idea's out to the world
cheers, and tell me what you think