When you have time, search for articles on 'curve fitting', there are some in the forum and quite a few on the web.
Too many indicators causes 'curve fitting' problems because the indicators are optimized to the data. and are probably going to fail in future.
I use the EA Studio a lot....... I have probably seen it generate 10,000 strategies in the past three weeks........ and the best strategies are using two or three indicators.....
When we first started with Forex Stategy Builder, we were limited as to the number of indicators. and we pressed for more.. and got 8 slots I think.
Then when FSBPro came out, there was capacity for 8 and we pressed for more. now you can use, I think, about 54 in total....
I do not think that many people who wanted to use a great number of indicators are still trading..... their strategies did not last.
Years ago, Popov warned us against too many indicators... and if you look in the old threads, yopu will see that there are some great strategies with only a couple indicators.
The test is Multi Markets........ if the strategy does not do well in the Multi Markets.... chances are it will fail with new data.
Even when it passes Multi Market there is a chance of failure because of the nature of the markets. Multiple indicator strategies do not do well with Multi Market.