its only good in theory and imajination, try using it in real battle ,where everyone using shield,immunity and heal/debuff removal.
-Han and itachi breaktrough combi is useless, sure remove buff and change the barrier , but we dealing no demage to enemy.
-breaktrough hanzo is sht, his Y skill is better , remove buff,immu,and shield, same like han + poison
-Lee and yamato for nine tail , sure , but we need for PvP not pve.
-Fu Yamanaka Y skill is much much better, can have 20% Leech Effect for Nin & Tai attack, it very good, the puppet only summon once in beginning but have more health
-Kurenai is Meh , she not good , not bad either, just so so , doesnt do much these day

and you know what better ??? you c*e Experiment Vial for for skill trial, and dont need to fully grind the book for ninja you would never use.

YujinTakara & RenjiAsuka all you can do is talking theory,

ohh kurenai is good , hanzo too, oh , lee is good to for bla bla bla , ohhh , yamato is cool , and itachi is good , can reflect debuf , bla bla bla.
but do you even see someone using all the ninja you talking about in the SWB or Matsuri ?? do you know why meta team exist ?? because it easier to to get meta than gathering for 200-400 frags of ninja. While you grinding for frags , you c*ready used a meta team with the coupon you saved , so whats the point of gathering all those frags ?? and the skill breaktrough is just minor improvement of the skill and not even good,still the same skill with additional effect, different with Y skill , its a new updated skill new effect more useful it basicly change useless skill into More useful skill, and player c*e it instantly using a vial.
what do you mean Vial is not practical, you can basicly CUT the time gathering those frags by a LOT, using 10k moon is much better rather than grind for whole 1-3 month because by the time you done, many player will already used meta and if you not on the meta side , you already losing.

Skill breaktrough is good in theory, but not practical.
it already proven useless by the fact no one using them as their main team(at least in my server bracket and yours too i believe), we need more Skill trial ninja because Player can actually use them by using vial instead to have grind for whole 1-3 month, while it still relevant ninja.
we need more skill trial ninja , not useless skill breaktrough.