Haven't seen them but I have heard of people having trouble with yeast settling in the tap and also with there being too much of the beer left over in the bottom. I probably should look into a new fermentor though. Mines starting to get a bit old.

Yeast dying doesn't sound like a fermentor issue. Have you been checking the gravity? One of my two fermentors never bubbles through the airlock and you have to really monitor the gravity to know when its done, that said I don't use the bubbling as an indication of fermentation stopping. Yeast dying sounds more like a temperature issue.