Unless the poison or disease is from The Spinner Of Shadows or a Pit Fiend, chances are it's an annoying box in the top of the screen that anal retentive players get worked up about but actually do very little to slow you down (if at that at all). Even the so called super-disease Mummy Rot didn't even bother me when I ran Wizard King Elite at level. Seriously, when THE disease doesn't bother you, there's something missing.
Mummy Rot deals 1d6 con and str per minute, if you fail your save, with the low DC and easy access to +6 or higher disease "immunity" item you will make the save at least 2/3 times. Making the save on average 2/3 times means that Mummy Rot will never bring you down because you're also healing at a rate of 1 per minute.

So here's what I'm suggesting, while diseased or poisoned you don't automatically regain ability damage.
Secondly, if you rest while poisoned or diseased you're not automatically cured, instead you make up to 10 consecutive rolls until you either die or get better, then the healing begins.