Angelic Buster as a damage class is quite good but their survivability is far too poor to call the class balanced.
For starters, Angelic Busters had their attack count decreased in favor for high damage, which is fair enough, but as the game mechanics were changed, Defense barely does anything to lower damage intake as it did and Angelic Buster has no defense for it to matter anyways, and Angelic Buster only recovers 200 HP from successful recharges (it never stated that she does this in any of her skill descriptions or skill guides, but I figured this out on my own), and her hit rate is so slow that you will always take in more damage than you recover. I would be in favor of having the 200 flat HP recovery per Recharge be changed to a 3% of max hp per recharge success. (Shade has a 1% HP recovery per attack, so with an Angelic Buster that has a 90% chance to successfully recharge but slow hit rate, aside from Trinity, which is still slower than bomb punch (but who uses that during bossing), it's almost the same rate of health regeneration and even Shade doesn't rely on that alone to keep the HP pool high)
The Damage to Shield scaling for Power Transfer is poor in which it still uses the % Damage dealt = x formula similar to the old Drain Formula, but to get a "shield" that reduces 50% damage upon hit, but should be able to absorb more damage via Shield per hit, up to around 65% to reduce shields faster but it won't even be enough to drain shields as fast as it's recovered. I will take 2k damage from monsters and I get no evasion chance from my own skills, meaning I'll almost always get hit with 2k damage on a character with only 20k HP for my level (201)
What sucks most about Power Transfer is that having it on is almost as annoying as taking full damage by not using it because the skill is non toggleable, which means every time you use the skill the shield will reset with 1000 shield, but also the Yellow shield gauge blocks half of my HP bar from being visible and is distracting when trying to monitor my remaining HP during boss fights. I don't really care how much amount of Shield I have because I'll always be doing damage to replenish it to 100% of it's max value. On the other hand, I do care about how much HP I have because 0 HP = Death while 0 Shield = 100% damage intake, which is less valuable than losing a life during bossing or my EXP when grinding (yes I do die when training normally because of this)
Long Story Short: Increase HP recovery from successful recharge from 200 HP to 3% of Max HP per successful recharge because it scales to high leveled character ranges of HP
Make Power Transfer passive and remove yellow gauge from HP bar while keeping shield amount visible (that's all it needed to know it's there) because it's annoying to micromanage HP during boss fights without a Pet that does it for you.
Increase shield absorbsion from 50% incoming damage to 65% incoming damage for better survival and shield draining pool because 1% of damage dealt becoming a shield that only scales up to 99,999 HP (or 100% of your max HP) would practically only require 1 hit to max the shield.
if either % HP per successful recharge or better damage absorbtion % from power transfer become too OP for Angelic Buster if added together, I'm willing to side with one or the other, but please remove the visual shield and make Power Transfer a toggle skill.