Ok, here is mostly speculations and putting small pieces of information together.
What we know is, that there will be 8 new hereos. We also know that there will be 4 classes and each class can take two routes. We all know about warrior examle when warrior can be berserk or knight.
So, 8 heores / 4 classes = 2 heroes per class. Then 2 heroes per class / 2 subclass. So i can assume that every single hero in new box will be representative for each sub class in the game.
Now, lets sum up information about heroes.
We all know Leroic of the book, (mage) and Widow Tarha (possibly a healer... maybe mage)
What left is two miniautres which are shown in that gaming magazine (link here : http://boardgamegeek.com/image/1249367/shnar )
Those two are definetly payable.
That big guy with mace, lets call him Billy the Mace (warrior - knight) and small guy with knife, lets call him Oliver Twist. (LINK: http://www.gametrademagazine.com/Home/1/1/58/591?articleID=117244 )
I will ignore characters printed on box due to the fact that first descent first edition box have characters from tomb of ice on it.
What is left are that beautiful Elf Lady (scout), Dwarf (Fighter Berserker) and some blue character which can be seen on table on http://boardgamegeek.com/image/1249367/shnar
Blue = Healer of mage.
Now, lets summarize
Fighters : Billy the mace (knight) X Dwarf (berserker)
Scouts : Elf Lady (archer) X Oliver Twist (rogue/assasin?)
Mages : Leroic of the book (sage) X blue guy on the poster (elementalist)
Healers : Widow Tarha (Shaman) X Great Unknown (bard or priest)
And i bet my overlord mug that i am 50% accurate
What is bugging me is which class will be guys Battle Mage Johnas or other characters which are not pure class oriented