At the risk of beating a dead horse.....
I put this in its original form on another thread, but wanted to keep all the Nessa stuff together in one place.
And so.....a run-down of one possible plotline of this episode that avoids some of the issues we've been complaining about.
Life is good at the beginning of this episode. The Valar have learned to work together, there is (apparent) harmony, and the great unifying project of the construction of the Lamps is underway.
BUT, all is not well. There are new, killer beasts about, and they are working in darkness and leaving gruesome carnage behind. One day, Nessa goes out to play with her woodland friends and stumbles upon this scene instead. Horrified, she rushes back to tell the other Valar. Yavanna is upset*, and Nienna comforts Nessa. But Yavanna is more proactive, and appeals to the other Valar to go out and fix what is wrong. Aulë is more like, let me finish building these Lamps first, then I'll help. Someone mentions that with the light of the Lamps, they'll be able to see better and prevent this sort of thing.
Queue Tulkas' entrance! 'I heard you needed some help,' and he is all excited to fight monsters. Melkor is annoyed, but tries not to show it. So, they tell Tulkas what is going on, and Nessa shows him the place where she found the carnage. Yavanna takes care of burying them. Oromë helps with the tracking. Nessa finds the survivors of her little band of critters and asks them what happened, but they are too frightened and distraught to tell her.
Ungoliant now makes her appearance, meeting with each of the trackers one by one (maybe not Yavanna). This can reveal some of the weaknesses of the Valar. By having Ungoliant target multiple Valar, she is both more threatening and less focused in her interest. She can show the same hunger towards all three, and be revealed to covet something each of them has. I think that three encounters like this can lend the story a very mythic feel, and get the right sort of vibe. If Ungoliant does try to lure or entice them, it can be seen as a 'Don't leave the path!' moment, rather than a 'come hither' gesture.
Nessa can be a bit naive and innocent, inviting her 'new friend' to help her in her quest to find the dangerous monster. Ungoliant can agree to help her look for the culprit. Oromë is warier, with a 'Who are you?' approach, but not wanting to be lacking in hospitality (think Aragorn addressing the 'old man' they think is Saruman at their little fire in Fangorn). But he is more intent on completing his mission than on keeping track of her, so she slips off... only to run into Tulkas. Since everyone is new to him, he doesn't realize she's not with the Valar. We might reveal Tulkas to be a little 'simple' here, dividing the world into friends or foes, and not necessarily being great at telling them apart without a little guidance.
Ungoliant will thus be moving in and out of these scenes, but will be very much 'other.' She can just fade in to the background at the end, fleeing the light of the Lamps, leaving the viewer a bit disappointed that there was no conflict (with her). But there will still be an action sequence where Tulkas and Oromë take on the pack of mad marauding beasts (rabid T-rexes?). Nessa hangs back at first, a little uncertain if she wants to be part of the slaying and mayhem. But, she sees an opportunity to help and then joins in the 'dance' of fighting. She and Tulkas are mutually impressed with one another, have each others backs, and Oromë smiles knowingly.
Then they go back to see the lighting of the Lamps and we get some Yavanna/Aulë domestic spat. They are the old married couple of the Valar.
* Not as unnatural as might be thought. Here is an example of a naturally-occurring mass die-off:
http://www.cbsnews.com/news/60000-antelope-died-in-4-days-and-no-one-knows-why/
But the point being that Yavanna is not going to be horrified by the circle of life, merely by something breaking out of the natural order of things and killing wantonly for no reason. Modern viewers may not be entirely comfortable with Oromë being a god of the hunt, killing innocent creatures 'for no reason' (do the Valar eat?) - so in this instance, we make it very clear what the reason is, and it is in the defense of other innocent creatures.
I don't expect the hosts to spend any more time discussing this plotline at this juncture, but wanted to throw this out there for people to mull over here. I am certainly open to suggestions for improvements on this scenario!