Except for the change to neurotoxin, the only real buffs for Azure Fang feel like they were created to buff her effectiveness in Kyuubi event rather than address her actual issues such as lack of CC protection and how crappy her healing is, especially with ignite being so OP as a debuff.

Regenerative Healing jutsu should cancel all debuffs AND THEN heal all units by 25% of Azure Fang's maximum hp. It makes no sense for Azure Fang to not be able to heal through fire when water is supposed to counter fire. The whole concept of the element wheel is the way that each element counters the other. Lightning beats earth because lightning deals so much concentrated force that no earth jutsu is able to make rock hard enough to withstand that force. Water counters fire because water puts out fire and water is thought of as healing, water heals burns. Water helps a fire scorched area regrow. Making ignite nonhealable is counter to the concept of how water counters fire.

Reserve Seal does basically nothing. 2% hp is nothing. To get the 10% attack if you have to be hit, but if you are being hit then you are probably being CCed as well. So you aren't going to get to make use of that stacking 10% attack gain. Since Azure Fang has no CC protection you will either need to bring along another healer or * Azure Fang in the back row where Reserve Seal becomes pointless. Reserve Seal also competes directly with her talent that increases the Ninjutsu and Attack of 3 water ninja by 40%. If Azure Fang is the only water ninja on your team you'd have to give get hit 4 times in a row to make up for the lack of 40% and even then you would still be losing because you start the match with the 40% increase using the other skill. I don't see many situations where Reserve Skill is the superior choice unless you know what team you are going to be facing ahead of time.

Curse Mark Test: This skill competes with Azure Fang's poison tai skill. The Poison Tai does more damage per round than a whimpy 20% increase in attack and ninjutsu. Especially because Poison Tai still poisons even if Azure Fang is CCed whereas Curse Mark Test is useless if Azure Fang is CCed. The only time I could see Curse Mark Test being the superior choice is when facing an enemy with immunity. However that is only because immunity operates as a game rule breaking cheat code. This is again a skill that seems like it was added to boost Azure Fang's performance in Kyuubi event. However you could have also taken the Water Clone which can acupuncture and interrupt as well as serve as a meat shield.