Games Workshop’s Adam Troke written an official 8th edition tactica for the High Elves.  It looks like a pretty good summary, and would likely give you a good idea on how the High Elves would fair in the 8th, at least from the eyes of Games Workshop.

The Children of Asuryan

Adam Troke knows a thing or two about the High Elves – he is the author of the army book, after all, and you would be hard pressed to find a more staunch defender of Ulthuan.

The armies of the High Elves are finely trained and superbly disciplined fighting machines. On the battlefield precisely ordered regiments of Spearmen and Archers, bolstered by cavalry, chariots and ranks of elite infantry form a glittering host. The heart and soul of any High Elf army are the regiments of citizen soldiers, the Spearmen, Archers and Sea Guard who answer the call to defend their island continent. The term citizen soldier could be considered deceptive to those who are uninitiated – for every High Elf devotes a portion of their time training in the art of war. What is twenty or thirty years spent mastering bow, spear and sword to an Elf whose life will span centuries if not millennia?

While the Spearmen and Archers form the centre of the High Elf battleline they do not fight alone, for the Elves of Ulthuan have many elite regiments whose prowess overshadows even the skills of the citizen soldiers. The likes of the Sword Masters of Hoeth, warrior aesthetics whose skill with their great swords is without match and the White Lions of Chrace, a ferocious band of warriors who form the bodyguard for the Phoenix King and act as his envoy upon the battlefield. Elegant Repeater Bolt Throwers hurl spear-sized projectiles into the enemy while brotherhoods of elite knights such as the Silver Helms or the legendary Dragon Princes lead shield-shattering charges into the foe.

Most fearsome of all, however, are the Dragons – gigantic monsters whose history and destiny is inexorably intertwined with the Elves of Ulthuan. These mighty creatures lend their wisdom and incredible power to the High Elves, sundering enemy regiments with claws and gouts of flame.

These then are the armies of the High Elves, a host of elite warriors whose skill at arms and preternatural agility makes them the finest fighting force in the world. Well led, there is no foe that they cannot overcome for they are the scions of Asuryan and their skill, intelligence and grace is beyond the comprehension of mere mortals.

On the Tabletop

There’s no army more elite than the High Elves in all of Warhammer. Their warriors are all experts in their own field of combat and used with care and precision they are capable of besting any foe. But such skill does not come cheaply and the High Elves are among the most costly warriors in Warhammer and, for all their prowess, they are individually fragile.

Strike Fast

The High Elves all have the Always Strike First special rule. This reflects their unnerving agility perfectly and means that they will simply always get the chance to wreak havoc on the enemy.

Fleet Footed

High Elves are universally swift – even their horses are faster than those of Men. This is especially handy when you’re marching into position. Dwarfs and Men have nothing on the Asur when it comes to getting about quickly.

High Stats

Elves aren’t shabby when it comes to Weapon Skill, Ballistic Skill and Leadership. This means they generally find it quite easy to hit the foe and, should the unthinkable happen, their Leadership value means they won’t just turn tail and run.

Anti-hordes

The High Elves can chew up hordes of Goblins, Skaven, Empire State Troops, Skeletons, Zombies, Bretonnian Peasants and so on without even breaking a sweat. Because they strike first (and will invariably have a higher Initiative so get a re-roll to hit) and they fight in so many ranks (two as standard, plus one for spears, another for the Martial Prowess special rule and another for a horde if you’re so inclined) they will cause untold carnage on the enemy. A large block of Spearmen will absolutely ravage a unit of Skaven or Goblins and emerge on the other side largely intact… which is just as well because such a unit will often have to kill two or three such foes before the battle is over!

Magical Domination

The High Elves have their pick and choice of magic – their own lore of High Magic and the eight Lores in the Warhammer rulebook. This gives you a massive arsenal of powers to choose from. I recommend using High Magic first and foremost – since Drain Magic and the Shield of Saphery are so useful (the 5+ ward save from Shield of Saphery can really make a difference for your fragile troops). Lore of Life provides a couple of great spells including a 5+ Regeneration save and a potential +2 Toughness for a friendly unit. Imagine how resilient a block of Spearmen would be with Toughness 5 and a 5+ Regeneration save!

Watch out for:

Being really fragile

The High Elves are expensive in points but they’re not especially tough or well armoured. In fact, the converse is true. This means that they’re especially vulnerable to being shot at and they sometimes struggle to survive in protracted combats. As such use their speed and hard-hitting nature to keep them alive and make sure you're always fighting on your own terms.

Overspending

There’s a massive temptation to overspend on elite stuff such as Sword Masters, Dragon Princes, Lords and Heroes. Resist the urge. Make sure your army has a good, reliable character or two but don’t get carried away. Unless you include plenty of Spearmen or Lothern Sea Guard you're going to get swept away by hordes of enemies, no matter how great your warriors are.

via Games Workshop.