I vote "no", as it's easy enough to undo with a cure minor wounds or a Heal check.
I like the sicken/nausea/daze, but I'm not sure it fits into the traditional poison structure anymore. Make it a unique ability, and note that anything that affects poison applies to the intoxicating bite?
All that's fine, but aren't there poisons with primary and/or secondary damage "sickened for X rounds"? I'm pretty sure DCv1 has them, and it's not so different than unconsciousness. I guess the stacking might need to be explained.
Yeah, there are poisons like that. The problem is, by default, the same poison doesn't stack. So if someone gets sickened on the first bite, they won't become nauseated on the next bite.
Borrowing liberally from troglodyte stench (another "poison but not poison" ability)...
Intoxicating Venom (Ex): A creature bitten by a plainsjan must succeed on a DC x Fortitude save or be sickened for 2d4 rounds. A second bite worsens the condition to nauseated for 2d4 rounds, while a third bite dazes the victim for 1 round. The save DC is Constitution-based. A delay poison or neutralize poison spell removes all effects from an affected creature. Creatures with immunity to poison are unaffected, and creatures resistant to poison receive their normal bonus on their saving throws.