heaving looked more into this, seems it just the marksman getting the short end of the stick
The spell casters gets bigger/more damage from learning higher spells.
The melee fighter gets a second attack(heroic ability dual wield) and "Find Weak Spot" melee special action can allow you to ignore armor for potential quite a bump too.
I haven't looked much into the rogues yet, but there is a sneak attack you can also increase from heroic ability.
so numbers do somewhat "go big" across the board, just not for the marksman =(
But as some of you pointed out it seems my expectations of "mirth and mayhem" isn't quite the same as free league