There are two types of difficulties, one is being unfamiliar with the game mechanism, just as you described when barricades got blown, enemy heroes show up...etc; the other type is the damage penalty for underlevelsThe first type of difficulty can be conquered by players, eventually everybody will know what to do about this game; the second type of difficulty cannot be handled only by player's experience. It is imposed by design for the sole purpose of prolonging the game's longevity. It is forced grinding.
First, I feel like there is a built in "trap" (the bad kind, not the orc killing kind) where players will spend all their skulls on common traps instead of champions and then miss out on what I think? is a critifical early game feedback loop.