Wraith shields?

[True!Ancient]

And when did they destroy an Asuran Aurora in a fair fight without breaking a sweat?

Have you not watched BAMSR?

[Gaeth]

Fair fight, ambushing ships coming out of hyperspace is not fair, and stealing a kill from a hive is not a valid kill either. People are probably getting tired of me saying this but we have seen nothing that indicates the Asgard plasma beams are extremely effective on Aurora shields, from what we've seen is that it is adequate.

Even if it did the Asgard had a long time to study Ancient tech and update their own weapons. Since the Ancients died so long ago some of their shields could even be antiquated by Asgard standards. Besides alot of the ships in BAMSR weren't necessarily destroyed in the initial attack, just distracted.