I believe gambling would be a good addition to the addiction disadvantage. It is a rather common addiction in the real world. Also, I agree that perhaps we should change the requirement to one induldgence per evening of roleplay. As the official room times only run two hours currently, having to roleplay half of that time using your addiction is rather taxing.
On the flip side, we could rework the disadvantage completely. Say perhaps all basic addictions are 5 GP. However, you can have a more serious addiction for 10 GP. In otherwords, you can have a 5 GP alcohol addiction but you can also have a 10 GP alcohol addiction. If you purchase the 5 GP alcohol addiction you only have to induldge, say, 15 minutes whereas with the 10 GP addiction you have to induldge for half an hour.