I am not sure if I would call it cheating. In the case of Teracoins, some kind of algorithm that makes hash rates more even would actually benefit the entire community.
Not sure what you mean but IIRC the formulation in AoBPMRS treats difficulty changes properly, it will work even if the difficulty changes frequently.
The question was how I came to this topic. The answer is that I was looking for some kind of algorithm (or even implementation) to hop to a different coin, as opposed to a different pool, when the difficulty goes up.