I think you have gotten some good hints on here.
To summarize:
Why trade ES on 30 min or less bars? I'm not saying it can't be done well (Buzzy comes to mind...), but gee you are really going for the gold medal with that choice. I certainly would not want to attempt it short of being in the old pits where I could get order flow information.
At any rate, I think traditional indicator systems are better suited to longer term trading. The reason why is found in analyzing the data. Some smarter people than I analyzed the data on various instruments and then found an applicable indicator that would allow them to take advantage of what they saw in the data.
So if you are hell bent on trading ES 30 min bars, I would suggest analyzing the data. My guess is you'll find it is an epic mean-reverting instrument, and so moving average cross-overs and the like will be useless.
I think a lot of newer guys want to say "I'm a Big Swinging D**** ES Trader". This is ego rearing up and this is a major, major problem. Are you out to prove something or do you want to make money? The two are often mutually exclusive in trading...