With the current critical damage formula, critical attack is pretty much useless. I will show how critical attack only accounts for only 10-20% of total critical damage.
The formula for crit damage is:
Critical damage = (1.5 x patk + catk) x factor.
Where patk = physical attack; and catk = critical attack.
The fact is, patk is usually a lot bigger than catk, especially with transcendent weapon. Add to that the 1.5x factor in the formula, and almost all the damage from critical comes from patk.
Giving an example. Let’s say you have full DEX build with lots of gems and got yourself 2500 of critical attack. And you have top weapon that gives you 5000 patk.
In that situation, patk will give (1.5 x 5000) x factor = (7500 x factor) damage. While catk will give only (2500 x factor) damage. In total, critical damage will be (10000 x factor), so your critical attack will only account for 25% of total critical damage! And that’s with a build totally focused on critical attack.
It’s even worst in fact, as patk also influences the “factor” in the formula. At average, most times patk actually accounts for 80%-90% of critical damage. So why invest on catk at all?
My suggestion is to change the formula decreasing influence of patk and increasing influence of catk. For example, make it like this:
Critical damage = (patk + 3 x catk) x factor.
That would make a lot more sense.