AbdulAlhazred
Legend
Treating it like an affliction more or less translates into:
heal xx ends!
The important part here however is, that a hard check is needed to succed, and endurance does not help here, as you already failed your fort check...
If it is a minion, 20 damage dave ends is too much, if it is not, it makes no sense.
If you need a heal check, you have not so much ime to call for help, but it is still possible, if a healer happens to hang around, and suddenly your HP make a difference between dying and surviving.
I think if you are in a combat situation then HS loss and maybe 'you can't heal' or whatnot are pretty useful effects. I mean a poison can certainly just do damage, but the typical thing with poison is that when you are poisoned you need to be cured, that's what really makes it distinct from just damage. It is also going back a bit towards the old style of poison kills. Well, now it doesn't necessarily kill, or at least not right away, but it may eventually kill you or leave you in bad shape.
So treating it like a disease and giving it an onset time and a check frequency seems cool to me. A quick poison might hit you right away and progress every round. A slow one might take hours or days but it also might have nastier effects. Sure, heal checks can be made, but they don't automatically cure you, they CAN make you worse or just not help at all. Heal by itself might not do the trick in all cases either, maybe some poisons require specific antidotes to even allow a check, or the check is very hard to achieve except with the right antidote.
Poison as it is now in 4e (if you can say much general about it at all) just seems rather uninteresting. It is just another kind of damage. Maybe it's ongoing, maybe there's a save ends effect involved, but it is so abstract it lost all its flavor.