The rumours surrounding the upcoming (still a ways off mind) reboot of Warhammer Fantasy all point to moving the timeline forward by about 200 years post End-Times and a consolidation of armies from the current 14 to 6 factions which will be amalgamations of current armies (e.g. vampires and Tomb Kings becoming Undead). There is also rumours that most of the units will be replaced too making it an entirely new game with a brand new set of models for each faction...
The Elves faction is easy to see as it merges 3 armies into one and the ETK fluff has them all buddying up in the forests anyway. There are also plenty of stories of different groups of Elves working together in the ETK novel, chief amongst them are the Shadow Guard, a mix of Phoenix Guard and Black Guard to form a new unit of bodyguards for the Eternity King Malekith. There is also the Avatar of Isha, a merged Forest Queen/Everqueen character and descriptions of Dark and High elf spearmen fighting together are prolific.
The way I see it, a potential Elves list would have the following sort of units
Mounted on: Stags, Eagles, Unicorns, Horses and Dragons
Named Characters from ETK.
Archers (probably with a wood elf spin)
Spearmen (blended Dark and High Elves)
Recon Cavalry (Reavers and Dark Riders)
Light Cavalry (Silver Helms and Glade riders)
Glass cannons (probably Dryads over Witch Elves, I think they're still hacking shit up in Naggaroth)
Shadow Guard (halberd tarpit, see above, possibly with Eternal Guard in there somewhere)
Heavy Cavalry (Wild Riders and Dragon Riders, the Cold Ones probably won't go down well in Lothern...)
Hunters (Killing Blow specialists, mixture of White Lions and Rangers)
Great Weapons (Executioners and Swordmasters)
Skirmishers (Shades/Glade Guard)
I'm not sure chariots are very fluffy in a forest and the rumours seem to suggest that everything is going to go supper fluffy...
Here is where it gets tricky...
Bolt thrower of some sort
Treeman, no brainer
Phoenix...I think this would work, certainly more so than a Khyribdis or Hydra
Sisters of the Thorne
I think the overall feel will be more towards the Wood Elves as the are the centre ground between the Dark and High Elves, they embrace both aspects of their nature rather than taking one side to an extreme. Also, they're all living in the woods and 200 years of it is going to leave a lasting impression...
In some ways I'm excited about what the future holds but in others, I worry if the rumours about round bases and skirmish style play is going to just make it medieval 40k, I love how different Fantasy is and it would be a shame if they mess it up too much.
That said, it's important to remember that just because there is a new edition, doesn't mean all the old books and rules will burst into flames, never to be used again, it might mean however that I need to stock up on some units...
I guess only time will tell.