i think the strategy tester is a good filter, it does show if a strategy has promise, reveals strengths and weaknesses of a given EA. Optimization helps mitigate the weaknesses and exploit the strengths. Live demo testing ensures that given real time live prices, the EA efficiently communicates with the Broker's server & executes as intended. Live real money testing proves the EA, with real results. whether it is profitable or not.

with mt4, one is able to "live real money" test with lot sizes as small as $100, or a penny a pip. given that brokers such as IBFX pay interest on demo accounts, but not on live mini accounts, i believe it is important to "live real money test" with the smallest lot size allowable to be sure that the EA can overcome all obstacles presented to it, eg, swap charges, mid day build upgrades, isp interuptions, nfp days, etc, etc...

my humble opinion only...