Paladin of Baha-who? |
While either of the first two are perfectly reasonable house rules, the written text of the ability makes no distinction at all regarding a roll of 27 resulting from a natural 19 and a roll of 27 resulting from a natural 20. Both will be parried if the swashbuckler makes a successful attack roll of 27, even if she rolls a 1 to do so.
If her result is greater than the attacking creature's result, the creature's attack automatically misses.
If I recall correctly, this issue was raised during the playtest, and they kept the original wording, indicating that this is in fact the intent of the designers.
Taenia |
Note that this is different than some other abilities like Snake Style which set your AC. In those situation a natural 20 will always hit because it doesn't matter what your AC is. Opportune Parry and Riposte is different and can even negate a natural 20.