I thought I could also make a synthesis of everything I have suggested or wished for DLCs so far, together with ideas of other people I have liked.
So here is what I hope or merely would find nice for the DLCs to come :
Integration of what is mentioned in lore but absent from the game :The missing places
Werebears
Stalhrim
Black ironwood trees
Saunas
Lore-friendly Volkhiars
Something around the assassin born with a knife in the place of his hand, mentioned in Greg Keyes' books
New places to explore :The places I would love to visit are the following :
The places mentioned in the previous games and supposed to lie in Skyrim, which are missing from the game.
The Castles of Glass and Coral of the Dreughs.
Roscrea.
Olenveld.
Stirk (cause it is probably a place of high tension between the Empire and the Thalmor).
Stros M'Kai.
Solstheim
Borderline areas : Blacklight, Heldon, Snowline, Fearfrost, the Temple of Twilight, Dragon Fields, Dragonstar, the Pale Pass...
Orsinium.
Maybe remnants of Umbriel.
Spoiler Some inner realm located inside the Geode veins of Blackreach, similar to the inside of Azura's Star.
Some Daedric Realm. Maybe the Battlespire.
The realm of the insect God worshippe by Nilichi.
Maybe Anequina or Pelletine (not both, cause it would be too much for a Shivering Isles-sized DLC), cause I would love to know more about the Void Nights, but I also think they would probably deserve a whole game, which is more than a DLC.
I would rather not see a whole new province as it would deserve an entire game. Similarly, I would rather not see a complete eradication of the Thalmor, as I would rather see the conflict between the Thalmor and Humans as a key feature in the next elder scrolls series. But the DLCs could prepare for it.
New quests given by deities :By the Divines among the Eight who don't give a quest in the game so far
By Talos
By Jyggalag
By Sai, Grellan, Ebonarm, Druagaa, Ius
By Shor
By Morihaus
By Trinimac (I know he's supposed to be dead, but some Orcs already tried to revive his cult)
By the Ancient Gods of the Foresworn
By the nine totemic deities of Ysgramor's Nedes
By the insect-god worshipped by Nilichi
More lore and interactions and plots around the non playable races :By non-playable races, I mean Giants, Falmers, Spriggans, Hagravens, Dremoras, Trolls, Whisps and Whispmothers, Goblins, Dreughs, Imps, Ogres, Draugrs, Men-of-'kreaths, Minotaurs, and so on...
I would love to be able to discuss with some of them, to find questgivers among them, and to discover more on them. Moreover, those who aren't featured so far in the game (and some of those who are) could provide new armors and weapons sets. If they worship deities that are so far unknown, it could lead to new realms and artifacts.
A falmer uprising would be nice.
More lore, introduced through engravings, statues, frescos, books and dialogue.
More diversity :In the flora and fauna (small creatures like bugs, sparrows, snakes, etc...)
In the scenery (that is, new places to visit, as I already said)
New weapons and armor types (spears, crossbows, slings, throwing weapons!) and fashions.
New creatures (like this soulbug or the Goblins we saw in the Game Jam)
Variations in fur and more diversity in the faces of the people of non-playable races
More dungeon types
More depth :More options and outcomes in the quests that already exist, new quests related to the already existing factions
More consequences to the choices one made
More possibilities of interaction with the NPCs, especially the spouse, trainers and followers
More depth to the economy, justice and politics of Skyrim ; implementation of the Moot
More werewolves
Possibility to join the Thalmor, the Silver hand, Necromancers, the East Empire Company, Stendar's Vigilantes
Possibility of betting, organizing [censored] fighting, arm wrestling, playing card games and chess-like table games in taverns.
More non-lethal ways of ending battles, fights and quests, and a better AI. Possibility to immobilize people and force them to leave their weapons and surrender. Much less people who attack immediately on sight : why do so many NPCs attack me without even knowing why I come near to them? For example, I could go to some Bandit lair in order to propose them a lucrative association leading to a clandestine trade...
More realistic animal behaviour and ecology
Possibility of farming
Forts which welcome some people who aren't necessarily soldiers and who seek shelter in exchange for providing services to the soldiers (in fact, more realistic life in Forts)
New factions :The Foresworn
The various city guards
The Thalmor
The Penitus Oculatus
The Morag Tong
The Camonna Tong
The College of Whispers
The Synod
The Silver Hand
Stendar's Vigilantes
A Seafarer's guild
A Pirat fleat (An occasion to meet Velehk Sain again?)
A Healer's guild
Skooma smugglers
A Necromancer's faction
A prosttutes' Guild
Beast-related warriors (Berserkers, Ulfhednars, Svinfylkingars)
Enhanced crafting:Armor and weapons deterioration through use, need to repair them
Spellcrafting
More materials
Various special forges
Weaving
Wood carving
Runes
More complex crafting
Use of alchemy in the making of alloys and tempering of weapons
Named soulgems, the nature of the soul should provide benefits and drawbacks to the enchanting
Possibility to add modifiers to the enchanting like "more efficient in daylight" or "more efficient against Clavicus Vile's servants".
Crafting and enchanting arrows
New features:Falconry
Healing Dragon shouts
Some Way of the Voice perk tree, which would require Dragon souls to unlock
Climbing abilities
New items, spells, quests, creatures, and more of everything!
Everything we saw in the Game Jam, except Dragon mounts and the Vampire lord stuff, which doesn't seem compatible with the existing lore on Volkhiars.
Good surprises!
Other :I hope there'll be at least three major DLCs, each about the size of Bloodmoon or Shivering Isles. Some minor ones besides them would be nice too.
Some people are complaining about the long time they have to wait before any announcement, but actually I am glad of that. The more we are waiting, the more time the developpers have to craft wondrous DLCs, and the more ambitious they may be.
What else would you like to see or what wouldn't you like to see among these? What are your own hopes and fears?