That is what Forex Brilliance authors think too and they have created a suit of EAs that trade on specific major pairs. There’s no bafflement as regards what to trade it on and whether it should work better on one pair or another. I think more developers should use this practice. Not only that, when you are trading by hand you should consider that for your manual system too. It is a matter of chance, after you test and change a system on one major pair, it’s sure to perform best on it. Naturally, I do not say that there aren’t any systems that are universal, but it’s’s a lot more difficult to develop and run such a system.

A little something to look up:

USDBOT is a 2 in 1 EA for two currency pairs – EUR/USD and USD/JPY. The system is built around a strategy of a group of veteran FX traders, which has taken them years to perfect. The Forex robot was built using the adaptive neural network technology which takes into account common trading strategies in addition to its own. Thus the Forex robot is able to adapt to different market conditions or trends…

Can’t hurt checking out. It seems interesting.