The curve of a stick is a matter of preference. The more curve you have, the less control, and most players find that a smaller curve results in less power. If a curve is too big the puck often goes high and misses the net which obviously decreases your chance of scoring.
Most minor hockey players think that a big curve on their hockey stick blades will improve their level of play and even improve the quality of their shots. This assumption is absolutely wrong. Great players in the NHL like Doug Gilmour and Theoren Fleury play with an almost flat blade and they manage to score and play better than anyone else.