The drow poison is really techy, but that is intentional. The drider (and the drow I designed to go with it) all used the same poison mechanic. Their poisons stacked with each other.
It would be crazy to run every poison this way, but in play it was a lot of fun for my group. With the drow plinking the PCs with poisoned blades and hand crossbow bolts, all the characters racked up a lot of poison points. It also made skirmish tactics, drow darting in to fire a volley and running away to wait out the poison, a good move.
In addition, the poison added another element of strategic thinking to the dungeon. The drow had lots of patrols out, and resting for 5 minutes wasn't necessarily a good idea. In the end the party got lucky and escaped, but they had to drag a couple PCs behind them.
I don't think that I'd use those rules as standard for poison, but it gave a nice, unifying mechanic to a wide swathe of monsters.
(In the end, the PCs never returned to the dungeon and the black dragon that the drow had held captive in the dungeon's eastern wing escaped and trashed the entire dungeon. I think the PCs were too busy chasing wererats in the city sewers to go back in time.)
EDIT: The mechanic works pretty well if it's the one complication the DM has to track. I wouldn't release it into the wild as the standard for drow poison, but if I wrote a drow adventure I might use it as a unifying, adventure-specific mechanic.