hmm...traderji has said a very important thing about simplicity. and kalyan has summed it up pretty well - "In fact any complexity in the underlying is justified only if it makes the interface, the actual trading simpler". just like the utility concept of CV.
i dont think there's any question of simple vs complex. what is complex for some is actually very simple for others. just because you have a so called complex system, you wont be a big winner. but just because you have some simple system that works in a big trending market cos u happen to be there, you shouldn't dance around saying it works, it works, so a simple system of mine is all that is required. cos history is filled with such examples of simple systems that failed miserably. not because the systems were SIMPLE, but the users did not see the limitations of such systems and kept using them even when the market changed.
Mark Cook used a simple system of tick, trin and ticki. marty sch used a simple system of interrelationship between bond-S&P. While David Shaw used so called "very complex" algorithms. and all of them became wizards. however do not forget that Dennis Richards, a one time wizard using a famous "simple" system, had to close his fund and retire in the end cos he couldn't adapt to the new market conditions.
so the question here is more about adaptability and open mindedness. once you have that, you use whatever is comfortable to you.
as for RJ's MAs, everyone knows that MAs lag. If he or anyone still wants to use it and trade on its basis, its perfectly fine. tomorrow when the market stops trending, if RJ can still use MAs on 1 min to 5 ticks or whatever and make money, its absolutely fine.
On the other hand if Asish wants to upgrade to Genetic Optimizers to get an edge, that is perfectly fine too, provided he can incorporate it in his trading.
The experienced members like CV, Traderji, Saint, Karthik and others can only point out the futility and pitfalls of using certain things. Its up to each individual to decide how to incorporate that feedback. theres nothing more to it. again i'll repeat, its not about discretionary vs mechanical, or simple vs complex. its individual approach to the market that eventually translates to an edge. how you get it is highly subjective and varies from person to person.