More in depth spouses.

Ability to kill essential characters. Specifically, the ability to first incapacitate them and if I desire, execute them. It'd fix Markarth's problems a lot more effectively than the buggy quest we're stuck with. If I want to fail a quest or make it unsolvable, I should be able to.

Fly odaviing like a horse
Shout that turns enemy in to bones

Real Werewolves.

this ^
and bacon

Some awesome ideas here. I was simply going to suggest more expansive cities but things like enhanced combat and more spells are necessary. Owning a keep (at advanced levels) wouldn't hurt either.

Ahh OK fair enough, I haven't actually used that feature yet so have no idea what it is or isn't like.

Multiplayer system. Id love to roleplay with other players in Skyrim

the system is OK at the moment, BUT it could be improved, it feels a bit rushed to me. i'd at least like to hug my spouse once in a while.
i like the way spouses will speak affectionately to you, but they genrally lose 90% of their personality.
i do not see why Aela, a tough warrior, would run a shop. there is a mod (still a work in progress) on Skyrim Nexus that is going to epically improve her, and fix this, but the other 3734d5783a.37 available spouses are still boring
the mod (Enhanced Skyrim Followers: Aela The Huntress): http://skyrim.nexusmods.com/downloads/file.php?id=11450
a must-have for Aela fans on PC
(sorry to anyone wiothout a PC)

More armours. Different regions having different armours would be nice.

Ok? Seriously? The current marriage system is about as shallow as it could possibly get. Run one quest for someone, put on a necklace, and they're willing to spend the rest of their lives with you?

I'm sorry, but I disagree. The current system is not OK. It's very poorly conceived from the start. Overhauling the spouses after you marry them is a start, but even be fore you get married needs some massive improvement. It really needs some courtship and romance.

hmm, on second thought, it's crap. hit some wood with an axe, they fall in love with you, even if you never touch another axe.
or ntake Njada, for example. she hates you, but once you complete glory of the Dead, she loves you and talks nicely

Spears

The ability to rebuild homes, businesses etc. in places like Winterhold and maybe forts, etc. and/or be able to start my own community in a hold, e.g., "DragonBaitburg".

I want [censored]s....

rabbits?

Wearing more than one ring.

That is one of my favorites too, but alas there are no heatsinks in Tamriel (and i'd rather have a Dragunov anyway )

Seriously, climbing, levitation or acrobatics. I'm sick and tired of being vertical movement challenged

1. Jumping Height Enchantment for Boots? Maybe x2,x3,x4 of Players current jumping height.

2. Maybe a x2,x3,x4 of Players current jumping height for a Vampire Perk Tree. Picking this skill would be optional for users.

I miss deadroths...and it would be awesome to be able to summon a Dragon Priest. Am I the only one that thinks they are more badass than the dragons?

I'd like to see more dialogue options. We are typically given a single option as a response to a lot of conversations that fly in the face of how our character is supposed to act. A selfish reluctant hero isn't supposed to be giddy about their next move, while a smart-ass humorist would want to say somthing that pokes fun at the situation.

NPC: "Dragons have been sighted in the vicinity of a guard tower, please help us."

Dialogue options:

1. "Don't worry, I've dealt with countless dragons in the past. Go find someplace to hide and get your family out of here."
2. " Why should I go out of my way to help you? Whats in it for me?"
3. " Well, I won't bother to question Aldrin's strategic sense in assigning such a large number to hit such a vitally important strategic location as a guard tower in the middle of nowhere...But I supose i can do somthing to calm everyone down."
4. "A real dragon? No way! I'm getting out of here!"
5. "Lets go get them! Follow me!"

Right now chances are we would be given a single option to select that drags our character into an OOC moment and potentially ruins the mood for us. This makes it fairly difficult to role play.

A way to customize the house i by like moving furniture around, purchasing multiple themes and putting new items I found out adventuring in it.

yes plz. for example, in sims 3, you caan hang stuff on walls, choose different styles of objects etc

Oh, and also the ability to say, "Maven, stop threatening to get the Dark Brotherhood on me, I am the freaking Listener, you stuck up ugly [censored], and also I stole your clothes 5 seconds ago".

Longer, more interesting guild questlines. Or house construction. Or all armors and weapons from past games including different variations of the same armor. MORE SPELLS. Spell making.