i only have played hammerwatch for week so im not too expirenced or what so ever but i do have some cool ideas to have!
Vampire:[ranged] has 65 hp but his skills consume health not mana and can heal him back
Puppetier:[ranged] has 25 hp and 55 mana has the ability to go inside a monster and use them as a "temporary body" dieing in it kills the monster not the puppetier " cannot do it to bosses or mini bosses
Engineer:[ranged] has 55 hp can summon turrets that cant move to fight along him and some special cannon shoot that rolls forward dealing dmg to all enemies
Engineer:[melee] has 75 hp can summon turrets that cant move to fight along him , an ability to ride his turret and be able to move around and shoot /move faster and bigger aoe radius
Beast:[melee] has 85 hp able to transform to a beast with higher speed /att speed and hp regen and no mana cost on transform or at all " maybe has rage meter or so
anyways if u like these little simple basic ideas ^^ feel free to comment and change or give ur own ideas