I always thought an underutilized area for human heroes was a pure warrior or combat hero. We have the spellcasters and paladins, but pure warrior-heroes are less common.
I'd likely come up with a General or Lieutenant hero, using non-magical abilities. Like a modified version of Defend. Maybe a rush or charge. Evasion, Critical Strike, and Drunken Brawler are all excellent bases for physically boosting powers.
Also consider this: In all likelihood, magical learning came to the humans from the high elves, so it stands to reason that there would be those among human mages who would study the more nature-focused aspects of elven magic instead of just the arcane. A human ranger or druid, that summon beasts and uses natural magic would be unique, and it also provides an interesting character, one who exists in neither normal elven nor human magical circles, but has instead chosen to follow their own path for their own reasons. Such a person may be quite defensive about their abilities.
I've always always liked the idea of a class that combines damage and healing powers, perhaps through the use of medicines, poisons, and potions. Healing elixirs and corrosive acids are just two sides of the chemistry coin, after all.
