-- More drugs! Skooma is fine, but use it with a Skooma Pipe? Then you get stronger effects!
Moon Sugar.... I need that daily fix o' Moon Sugary goodness....
-- Culture-fitting creatures. Morrowind had the likes of Cliff Racers and Alit, and although I'd probably shun them off for being 'Odd', the unique, excellent atmosphere of Morrowind iteself made the creatures blend in and fit perfectly. If they could do it so well with Morrowind, then there's no reason why they can't take out some of those damn generic monsters and replace them with newer, unique creatures for the TES 5 world. If it's in Skyrim, then can anyone say 'Heavily Coated in Fur?' *ahem!* Wampas from Hoth in Star Wars.. *ahem!*
-- New Spell Effects that I'd like to see:
'Wisp': This sends a ball of radiant light ahead of you that moves at a moderate pace in a single straight line until it hits an obstacle. When it reaches an obstacle, it turns in a random direction, and continues moving again. Stronger effects make the wisp last longer, and shine brighter in the direction it is moving giving it a flashlight-like function.
'Levitate': Simple enough, this would be the same as in Morrowind.
'Mark And Recall': As above, this is like in Morrowind.
'Wind Magic': At its simplest, Wind spells simply knock an enemy back to the ground on touch. But with its ranged counter-parts however, it also cuts into the enemy as it knocks them back. Plus it'd be awesome to watch over and over xD
'Push / Pull Humanoid': There are two Spells in one for this effect; if you make the Spell as an 'On-Touch' spell, then it pushes the victim away several metres. If it's an 'On-Target' spell however, it pulls the victim towards you, landing face down by your feet. The stronger the spell effect, the further you can push enemies, and also the heavier the enemies you can actually use it on, since obviously a weak version wouldn't work on something like an Ogre.
--Unmarked Factions. Just like how Oblivion has Unmarked Quests, I'd like to see mini-factions that have a name, but no Ranks or means of advancing. Not even any quests! They don't appear in your Factions list, but instead offer various benefits when interacted with. For example, there could be a crime ring that meets up every Sturday at Midnight, and by attending the meeting, you gain a decent amount of money. The Deadric Cults scattered across the land could also be Unmarked Factions, whereby joining will allow you to buy Deadric Spells and Alchemy Ingredients from their Leader.
And so this brings me to my next point...
-- Deadric & Divine Magic. Both the Deadra and the 9 Divines should have their own Class of Magic. Deadic Magic, we've already had minor experiences with in Oblivion; Martin being a former Deadra Cultist; learning some basic rules of Deadric Magic; The Mythic Dawn Armour, heck even learning how to join thw Mythic Dawn! With these, along with us evil players' visits to Deadric Cults, there is NO reason not to feature at least some basic Deadric Magic. Also, you should gain access to certain high-level Deadric Items and Spells by completing certain numbers of Deadric Shrine Quests, and by doing certain Side-Quests which involve Deadra. Maybe they could even slip in a high-powered 'Summon Oblivion Passage On Self' Spell, for those who complete all the Shrines
As for Divine Magic? Well it runs on the same concept. You have basic Holy Magic, and by praying at Wayshrines, you not only reap the usual benefits, you also gain access to high-power spells by praying at certain numbers of them.
*Ahem!* 'Summon Divine Wrath On Target' *Ahem!*
But if this is set in Skyrim then they don't have the Divines so.... ignore the Divine Magic
-- Lock Containers. With all the Thieves runnin' around Cyrodile in Oblivion, I think we can only expect more Criminals in TES 5, and with stronger AI too. With this, an Adventurer is never safe, which is why you need to Lock your Sh**! Also, since NPCs have their own Stats, some would be able to actually pick your Lock, so Very Hard is essential!
Maybe they could even include a Spell which makes the Container/Door unpickable without a Key
-- Travelling Enchanters. One thing I always found unfair, was how only people with access to the Mage's Guild could Enchant objects. What if a Warrior wanted to add Elemental Damage to their Sword Of 'Epic Mass Destruction'? They can't. That's why I think you should be able to meet Enchanters in Shops, and even out on the roads who will happily Enchant your objects..................... for an increased price.