Mine is unlikely, but I would like to see the proliferation of small-scale magic as the game develops. True magi should always be rare - those born with the actual talent for true, terrifying magic - but I would like to see significantly weaker, cantrip-style magic and talents with very narrowly focused magical potential eventually start to spread (things like lycanthropy, the use of runes and rituals to slightly bend the rules of nature to one's advantage, etc...) once people work out how to trigger them and discover common methods.
I'm also very hopeful for creature grappling. Players being able to grab a creature and tussle with it, or climb it if it's big enough (Monster-Hunter style), and also to be grappleable by creatures (small creatures may bite or latch on with limbs to attack; large creatures may simply try to eat you or pin you down and ravage you).
Completely different bent, and perhaps not so relevant to the topic... but I would like to see CoE's optimisation refined so much that we can have thousands of players and NPCs rendered on a player's computer with no latency. I want to be able to watch an entire battlefield from elevated ground in full detail.
This one I know won't make it in... but I would like to see cults that persist for long enough eventually create figures of minor divinity through the strength of their belief. Be it through holy/good means (faith, prayer and devotion to an ideal or force that isn't one of the established gods) or unholy/evil means (blood sacrifice, the affliction of misery and hurt upon innocent people, or outright war upon the established religions), I feel that if a cult gains enough influence in the world, it should influence the world itself.
Lastly: I would like to see a completely unique technology tree. It's safe to say that ballistics was one of the core innovations that drove humanity's development from the point of its conception. What might have happened if humanity discovered a means to exploit other natural forces they way we did explosions? What effect would that have had on the societies that mastered each stage of those technologies? A few artists have explored this, and some very few ideas (Steampunk, for example) were fantastic enough to become central fantasy themes. A completely unique and properly implemented tech tree would be mind-blowingly amazing in a game like this.
Unfortunately, for all the appeal of my ideas... most of them would be hell to code >.>