The Barbarian and the Sorceress were the pretty standard classes to be added into a new Diablo game, the Druid was a community requested class (though I didn’t like it’s design as Diablo shouldn’t look like as World of WarCraft, it looks like Malfurion in a more fat version), as I am a big fan of the Demon Hunter Class of Diablo III, I believe they should add the Class into D4, of course there are more options as Nephalem races are many …
*btw any news for any new lore official book? ‘’ The Art of BlackHeart’s ‘’ maybe (it would be a good title, with a spider anime as the book cover)
I hope there is only Barbarians and Demon Hunters with an arcade feeling to the gameplay. If not then I hope Panther is a class (half cat half human).
But I saw the trailer and it seems wizard is in it.
Sorceress, the biggest lie of the century, you wanted to mention, I believe.
I am not a big fan 
Just don’t reboot the classes. Be creative, bold even, maybe a new class.
An idea would be to mix classes depending on the traits and skills you choose say druid-barbarian, demon hunter-assassin, paladin/crusader-monk, necromancer-witch doctor, sorceress-wizard.
But then we’d be getting awfully close to treading on that fine line between MMO and ARPG. I think the various classes should be clearly defined with their own set of unique skills and talents.
Take for example in Diablo 3, we have Barbarian, Crusader and Monk. All three of which are classified as melee fighters. But that is where the similarity ends because no matter which way you cut it, each class plays entirely differently from one another.
A Barbarian should be a Barbarian. Druid must remain Druid. Sorceress must remain Sorceress.
Sure, they can bring in more Melee, Magic/Caster and Ranged classes, but each one must have absolutely unique traits that makes play style different for each one.
I a little disappointed: just 5 class, is few.
The 3 revealed is ok, now i hope the last 2 the Demon Hunter, and the Crusader.
But then where is the Necromancer? 
I wish 7-8 Class in start, and 2-3 news in expansions or dlc’s.
Before the BlizzCon, i hope these classes:
Barbarian
Sorcerer/Wizard
Druid
Demon Hunter
Crusader/Paladin
Necromancer
Assassin/Rogue
Warrior
And after this: maybe Witch Doctor, any Fallen Crusader/Death Knight, maybe Monk. And i hope any Ranger class (melee and ranged skills).
Now i a little disappointed.