Well, it sort of is, and sort of isn't, a hackenslasher. There's a lot of fighting in the game, and most quests consist of going out and killing X named foe, or kill a certain number of a certain type of foes, or collect a certain number of items off of the bodies of a certain type of enemy.
THere are other types of quests, however, including bar quests. Two examples of these:
1) If you're Alliance (human, dwarf, night elf, or gnome), you can help a gnomish brewer play a practical joke on his rival dwarvish brewer, by sneaking into the dwarf's basement and replacing a cask of the famous dwarven ale with a cask of funky-spiked ale.
2) Similarly, if you're Horder (undead, troll, tauren, or orc), you can help an undead apothecary test out a new poison on a dwarfish prisoner, by gathering spider venom sacs for the apothecary; he'll then brew up a fake dwarven ale with the poison in it, which you give to the prisoner, who drinks it and then dies in agony.
So not all the quests are killing quests, though most of them are. Fortunately, the combat is a lot of fun: a one-on-one battle lasts about thirty seconds to a minute, and you'll spend that time mixing and matching your special moves to maximize your chances of success. In an average thirty-second battle, I'll do about three or four special maneuvers in addition to my basic attack. If you party up with other players, your options increase dramatically.
I've not encountered voice and speech, but I can't say for sure whether that'll be included in the final game.
The game uses both skills and levels. You gain a skill point every 600 XP, I believe, meaning you gain more and more as the game goes on; you spend skill points to gain a single level in a skill. Learning how to mine minerals might cost 5 skill points; learning to use two-handed swords might cost 30. Once you learn a skill, every time you use it successfully your level in the skill goes up by 1 until you reach max in that skill. Gaining a level qualifies you for higher maximums in skills, as well as for new abilities and spells, and increases your basic stats (strength, spirit, etc.)
Mostly what impresses me about the game is the attention to detail, and the gorgeous environments. Apparently in most games, travelling between regions involves a cutscene; in WoW, it's all real-time. The undead will hop on a giant bat in order to traverse great distances, and in real-time you'll fly over hills and valleys, across farms, through volcanic regions, and so forth. As I'm wandering the game's immense areas, every now and then I'll look up in the sky to see a zeppelin floating overhead; I know that there are players on that zeppelin looking down at me on the ground.
Daniel