Read again Marvel's pitch regarding the Dark World:
Marvel’s “Thor: The Dark World” continues the big-screen adventures of Thor, the Mighty Avenger, as he battles to save Earth and all the Nine Realms from a shadowy enemy that predates the universe itself. In the aftermath of Marvel’s “Thor” and “Marvel’s The Avengers,” Thor fights to restore order across the cosmos…but an ancient race led by the vengeful Malekith returns to plunge the universe back into darkness. Faced with an enemy that even Odin and Asgard cannot withstand, Thor must embark on his most perilous and personal journey yet, one that will reunite him with Jane Foster and force him to sacrifice everything to save us all.
Right: who is this shadowy enemy? True, Malekith leads the Dark Elves and has vowed revenge... but does he really use this Aether or is the Aether using him?
Let's take a walk without priori claim of knowledge as who is the villain in TTDW. What do we see? Elves getting a thumping because Bor has captured the Aether. We also see that Bor does not go after the Elves: what we see is that he is very afraid of the Aether down to consigning it to some sort of prison. Just like in IM3 when we meet the 'nice' Killian humiliated for Stark. And we know this will come back to haunt IronMan. A good deed never goes unpunished...
From then on, what we see is a very active (shall we say bossy?) Aether driving Jane to him? Using the coming conjunction side-effects: the gravitation/realms/dimensional holes as to attract her attention?
Who then invades Jane: not Malekith.
Who triggers the awaking of Malekith but the Aether?
Who defends himself from the bobbies and Asgard's finest but the Aether?
Who because of Frigga's trick misses his appointment with Malekith but the Aether?
It is always the Aether who leads Malekith? Never the opposite. The Elven Lord is a follower, a superb henchman giving the Aether a physicality but always the boss is the Aether. Down to showing to Jane his plans despite being a very mute villain: just like any CMB villain has his cackling moment whilst disclosing his great plan to the hero...
Earth it is as the target and again Malekith follows his boss orders. And it is the Aether who rightly invades the realms like Loki led the Chitauri...
It is the Aether who takes over Malekith's body... and shows to Loki how to die and survive a deadly blow from Thor. Better he shows Loki how to take over as a disembodied being a physical body inhabited by the body's owmer spirit/mind. The power, the real villain who leads Malekith and Kurse to his nefarious tune is the Aether.
Down to the post-credit scene... Care to remember. We all fall for the revelation of the movie last scene... then the credits roll and who is prisoner and probably released in the wrong hands but the Aether... just like we could see that Loki was going to go after the Tesseract.
The cliff-hanger says it all: the villain has once again escaped and the realms are not safe.
The Aether has won: he is safe from Asgard and he is now able to carry on his plans. One down: five to go... Ragnarok is still on the equation.
As clearly, the Darkness wants to cancel the Light. Cancel the existence of Asgard...
Thanks for your thoughts.