That combined map news. No idea what type of armies skaven, lizardmen, dark elves, or high elves will have though. Do they hold to traditional archetypes like high elves are spellcasters? Also we're still on the main page. Feels weird.
High Elves are pretty tradional, elves in general are supposed to be somewhat more elite/skilled. Afaik they have the second-best mages after the Slann. They've got armored infantry, specialized archers, strong cav, chariots, a number of flyers - three different types of dragons, two phoenixes, great eagles and a flying chariot/warmachine - and ballistas for artillery. They're just all-around good at everything, really, only missing monstrous infantry and giant-type units
Dark Elves are pirates with a slightly more agressive army, perhaps. They also got armored infantry, elite melee units (Executers are sort of their HE White Lions), repeater crossbowmen that have an increased firerate at short distance, lizard and caster cav, unarmored witch elves (the half-naked female elves in the trailer), monsters (two types of "Hydras" and the awesome Medusa). A strong magic lore that focuses on buffing their units. DE and HE were sort of the OP armies in the last edition of WHFB I believe
the Lizardmen have the best mages in the game (Slanns), slow durable melee core units (Saurus Warriors), Ogre-type units (Kroxigors) and smaller skirmishing skinks that fire a lots of poisonous blowdarts from a short distance and a bunch of huge dinosaur units of course. They don't seek to expand their realm, they protect their ruins and breeding pools from invaders and believe they were created to stop Chaos
the Skaven have a lot of cheap expendable ratmen (literal cannonfodder as their rules allow them to fire into and through their own units). They have four major clans:
Pestilens - sort of cultist-like, they specialized in spreading diseases
Eshin - assassins and infiltrators
Skryre - they build dangerous and unstable experimental weapons that tend to explode a lot, killing their users/crew
Moulder - the breeder clan, they create mutated rat ogres, giant rats and so on
there's usually quite a bit of infighting between those clans. They are guided by the Grey Seers, mages who follow the Horned Rat who later became one of the Chaos Gods in Age of Sigmar. They can also summon a rat demon