I think it is a matter of both, because mostly the blend depends on the tobacco used and the process it underwent before being rolled; but burn too fast (ergo hot), and it'll go bitter. Angle the cut, it'll be delivered differently (like different glasses of wine). But mostly the first.I'm real curious about the flavor development question, myself. Is the progression of flavors dependent on a different composition of tobacco along the stick, or is it more of an issue of sustained combustion, temperature and exposure of the palate to smoke?
-Charles