According to Dierk Droth, the VP of Engineering for NinjaTrader, the upcoming NT7 beta will include a Monte Carlo simulator.
Monte Carlo sims are a way to produce random data to simulate different types of market scenarios and events, so that your strategy can be tested in a way that will preclude it from being curve fitted to historical data.
Although I am not currently pursuing automated strategies, I do still believe backtesting is a way to improve your trading. I use backtesting to find better values for indicator settings, or to just prove in a general concept if my theory works or not.
Additional details on the Monte Carlo simulator, as well as other NinjaTrader 7 features, are expected to be released within two to three weeks (by the end of June 2009).