Looking back some more on this I think another option could be to just give new players a starter deck for hero from each human class. Compared to competition, SE offers far less free stuff at the...

Also reading info on 10 heroes may be too much as well, especially if you will provide more details for each. So maybe reduce choice to 5 starter heroes, one for each class eg Boris, Eladwen, Victor,...

One thing that comes to mind is that heroes used in tutorial game may skew new player's selection towards those 2 heroes. If that is to be avoided, option could be to use heroes that won't be offered...