Well i recently was playing oblivion. Then i wondered what would be a good idea to bring back from oblivion and put in the new game.
Also things from Morrowind Can be included,

I'd like too see the Dark brotherhood come back into this game.
Being able to too own your own castle from a DLC battlehorn castle.
Also Oblivion gates would be nice too because the armor you got in the gates were nice.
And also from morrowind id like to be able to turn into a werewolf, or like in oblivion too turn into a vampire would be cool as well.

Or how about a whole new concept of Any Ideas?

sigil stones... yaaay!

I'd like some skills and attributes back.

throwing darts

What would you Bring back From Morrowind And Oblivion!

The possibility of failure at tasks. Morrowind was a bit too brutal for most people's tastes, but the idea was good. Using Oblivion's ratings of Novice, Apprentice, Journeyman, etc., one should be able to cast "Novice" spells without failure by the time they hit 25 skill points, but would have a 50% failure rate on Apprentice spells. Each point of skill would decrease the penalty by 2%, so by the time you reach 50 points, you would never fail at Apprentice spells, and so on. I never liked Oblivion's "can't even try at 24 and can't possibly fail at 25" game mechanics; they took the risk and reward out of the game, and left it as a flat and pointless "grind" to reach the next 25 point boundary.

The imagination that made the world of Morrowind.

The great music.

Please not bliviongate:
Predictably spears, crossbows and birthsigns
Less predictably perhaps item enchantment values, shipwrecks and grottos