it's fan-speculation on my part, but Rafaela's "feats" can't be ignored:
1A. Rubel tells us that Rafaela is as powerful as her older sister Luciela. Unfortunately, we don't know if he means Claymore Luciela or AO Luciela. At the very least, Rafaela is a rank 1, like Luciela was, or Rafaela can be even more powerful than AO Luciela!
1B. I do NOT accept that Luciela is the weakest of the 3 original AOs, the "Unholy Trinity" -hehe- (Isley, Riful, and Luciela), as she battled Isley to a draw, actually Isley was damaged and unable to chase after her (maybe even being slower then she is, and thus futile to chase after her, because if he was faster than Luciela or if he had enough yoki/energy left, then why would he not "run down" Luciela and kill her off?), whereas I don't think she was damaged by him at all (correct me if wrong), and Isley was as sapped/drained/exhausted of Yoki/energy as she was, if not more so...
2. Rafaela did not fear AO Luciela (nor Irene nor Clare+Jean), she could be sent to Assassinate anyone by Rubel, so she must have been that powerful.
Now, we don't know if Rafaela ever actually fought/engaged against Luciela when she Awakened at the Org HQs, maybe she did, or maybe she (and Luciela) didn't attack/fight each other. We don't know.
But, Rafaela sure had confidence going to Luciela after the Pieta Battle, with Isley and Priscilla right near by.
And, if Galatea speaks true, Rafaela (along with Renee) were spying on the Pieta Battle, unknown to everyone. What if Rafaela could have been sensed (she couldn't be due to her NYS status... but what about Renee?... hehe), so I'd say she must have been powerful enough to take on at least Rigardo, if not Isley as well... but not Priscilla... Rafaela's not that powerful... right?... gulp....
3. as has been mentioned above, Rafaela was "The Assassin of the Organization (well, Rubel's Assassin actually, hehe)", she was that powerful and had the NYS status as well, indeed making her the perfect "Assassin", to kill off who knows how many top ranked/powerful Claymores... that the "purifying" "Spiderman" male AB couldn't handle or nor hard enough missions to kill of them.
4. Rafaela partly resulted in the powerful Destroyer, so Rafaela must have been powerful herself.
5. Rafaela, even as an offensive type, could even Regenerate the difficult eyes (but she CHOSE not to Regenerate her damaged/missing eye).
6. Rafaela WAS a VERY POWERFUL YOKI USER!
A. Soul Link
B. Powerful Yoki Sensing
(she hunted down Irene and Clare+Jean easily, once Irene released her yoki to do her Quick Sword, and according to Galatea she had secretly spied on the Pieta Battle as well. Not to mention, that she immediately sensed/recognized Trainee Teresa's true Power Level, which NO ONE else could do...)
C. Mind Transfer (saving herself by putting herself/her mind inside of poor Clare's head/brain/mind)
D. She WAS able to challenge the Destroyer, despite saying that it was too powerful for her, breaking through, to warn and save Clare's life.
E. She was able to attempt the "God-Like" whatever she was actually performing "with what Rubel had taught her about doing in regards to Luciela" with dead Luciela's corpse, which she failed and incompleted resulting in her merely being half-merged with dead Luciela's corpse and somehow resulting in the creation of the Destroyer within her head/brain/mind.
F. She's the oldest or longest living Claymore, even still now in ch 113 - I think.
G. Regeneration (as mentioned already above)