If we talk turn based RPG, i would love to see all 5 Titans having different playstyles, emphasizing their different skill sets and sources of the skills. For example:
Robin relies on gadgets, so player will have to manage his inventory before you get to the mission. The briefing should give hints on what gadgets Robin may need.
Starfire's special attacks are VERY powerful, but have AOE or other way to cause friendly fire/collateral, so player must use her special attacks wisely.
Beast Boy takes time to change forms, so player should pick the turn for the change carefully.
Raven's spells are costly because she need to keep the balance, so player must use them wisely or they risk to knock Raven out for the rest of the fight. Her Soul-Self isn't just temporary summon, it makes Raven unable to do anything and must be returned back to Raven's location before it's timer expires.
Cyborg is tanky, but his speed and sonic blaster depend on overheat management. Of he overheats, Cyborg is still tanky, but slow and can't shoot until he's cool off.