Red dots = Where heroes would stand
The level designs get boring after a long time. I don't think it would hurt too much to add new types of levels, possibly with new enemies resembling heroes, like Kai, Leonidus, or Matsuta.
The beach levels would consist of mainly Kai look-alikes, healers like Yasmin, goblins, and sometimes even paladins. (Hey, they need vacations too!)
Some ideas for enemy names and abilities found in these zones:
Seafoam Tide-Rider (Green Kai)
High Tide - A copy of Kai's Surf's Up but a bit greener in color, instead of reducing the damage of AoE attacks, it instead reduces healing effects for a couple turns.
Tropical Trumpet - A copy of Kai's Call of the Deep, but just heals and Pumps one ally (your enemy).
Volcano Surfer (Red Kai)
Flaming Splash - Kai's Backsplash ability, but instead has a chance to light your heroes on fire instead of applying Backsplash.
Volcano Call - Kai's Call of the Deep, but instead just buffs self and one ally's attack stat.
Vacationing Knight (Blue or Yellow Augustus clones)
Possible abilities (Blue):
Lay Back! - Taunts, and heals himself.
Lazy Swing - Melee attack on one of your heroes, lowers energy of the target by 1.
Possible abilities (Yellow):
Soak In the Sun - Fully heals an ally and gives Burn Immune, and Intensified Light Immune.
Solar Charge - Boosts Skill of team for a couple turns.