Wormwood said:
I'm going to have each monster's stat block in front of me during the encounter anyway, so I don't really see the problem.
As a DM, you only need to memorize the core rules. Exceptions (like unique monster abilities) are only necessary to know for the duration of an encounter.
Of course you'll have a monster stat block in front of you. Voss wasn't saying otherwise.
The question is: Is your statblock a single line of numbers (Initiative, Hit points, AC, Attack modifier, Damage, Saves, Key skill modifier)
Or is your statblock a full page of rules, exceptions, and other special cases.
Finally: in my experience, most gaming systems that rely on "special cases" rules end up with some conundrums that give DMs headaches.
Example:
Player 1 has the ability "Riposte"--whenever an attack against you misses, you get a sudden counter-attack against that foe.
Monster 1 has the ability "lightning attack"--your attack is so sudden that opponents cannot make a counter-attack.
Player 2 has the ability "first blood"--your first attack in any encounter is always a hit.
Monster has the ability "Parry"--the first attack against you in any encounter is always a miss.
Now my example above may look extreme, but the large the rules get, (and the sloppier the proofing), the more likely you are to end up with examples like the ones above.