Sup, There are two things we need to come to terms with before we start.
Every team needs two initiators to start a combo, one every round.
Every team needs two tanks, to frontline against enemy standard attacks.
Every GOOD team has at least one method if interuption/control
Also, every good team requires an overlying theme/strategy. (for example, anko users go for fire teams, Yamato users go earth teams, Juugo users go curse mark, kon*ers go either tag or akatsuki, so on so forth)
Kurotsuchi is an interesting ninja because she has a status effect unique to her. Slowing does more than just "slow the enemy down" she basically interupts the entire enemy team for 2 rounds.
Thus she is an invaluable asset to any team, whether or not she does alot of damage. However she is purely a support, she does little to no damage, but she does have good potential for comboing.
This is the better team I've found for her for a fire main.