I havent read the suggestions above because im too lazy to scroll up but i have some ideas that could be added.
Yuki Clan The Yuki Clan in this game only have one offensive Nin based jutsu. I suggest adding:
1. Certain-Kill Ice Spears - The User summons Ice Spikes coming from underneath the ground.The spikes move forward atleast 5 tiles and will leave the user unable to move until the jutsu is finished. Damage based on : 0.75 x Nin. Idea inspired from
naruto.wikia.com/wiki/Certain-Kill_Ice_Spears2. Ice Release: Tearing Dragon Fierce Tiger - This jutsu allows the user to manipulate water and wind to form ice and form it into an Ice/Snow Dragon. You would need to require a nearby source of water in order to use this technique. (Basically you need to be standing "on top" of water to use this jutsu). The jutsu would last for about 10-15 seconds and would be controlled using .WASD, its damage would be 1.5x Nin and would require 60%+ CC to perform and of course would have a long CD. Im thinking it would look like the current Suiton: Suiryūdan no Jutsu but more Snow-ish xD.
naruto.wikia.com/wiki/Ice_Release:_Tearing_Dragon_Fierce_Tiger2.5: This jutsu could possibly leave an ice trail, that could bind/freeze an enemy like that Sticky Jutsu that can be learned in leaf and requires sution affinity.
Kubikiribōchō1.This sword has no ability atm so i suggest making this sword Assassination exclusive. Instead of being able to learn Assassination at ?? SS and being a villager of the Hidden Mist, give that jutsu to the Kubikiribōchō only.
2. Boost the damage of damage of the Kubikiribōchō user everything they accquire someones blood using the Kubikiribōchō. Ex: Thurnis hits Moo for 32k dmg, then the next time he would hit Moo, his damage would 32500 then 33k etc.
Inuzuka ClanThe Inuzuka clan should be able to tract someone using there noses. Ex: A Noob raids leaf -> loses 90% HP of his Max -> He uses the Invis jutsu and runs away. An Inuzuka should be able to stand over the splash of blood left by the raider and be able to track down(using their nose) the raider or know his coordinates like the Aburame clan is able too.