What Pips Expectancy do consider as good? 5 and above? or as long as it wont fall from 2pips?
That's a personal preference. I consider an average of 2 pips per trade to be the very minimum, just for the simple fact that I'm mostly using ECN accounts, which charge you commissions to execute the trades; so if you make an average of 1 pip per trade, and pay the broker 0.8 pips, how profitable do you think you can you get when you add up the other costs of doing business?
The lower the Pips Expectancy it is, the higher the chances that you'll get a high deviation from the 'expected' performance. Even 2 pips is low, and I'll use an EA that is making waves right now, with its astonishing returns (thousands of %):https://www.myfxbook.com/members/milliondpips/million-dollar-pips/114107
That EA has a Pips Expectancy (as of now) of 1.86, which to me indicates a very high chance you'll get different results (and most likely worse) than the 'official' account. If you read through the tread of that EA, you'll see how people are trying to get various VPS/broker configurations, but still most of them ending up with losses. So basically the system is great, but you cannot get that performance in your account. 😄
Also, even more important than the Pips Expectancy is the Expectancy Ratio, at least for me. The higher that number, the better the trading method. I suggest you try to calculate the 2 formulas on trading systems for which you can find more than 100 trades. Then search for more than one account trading the same system. You'll see that, in general, the systems having repeatable, consistent results, are the ones with higher Pips Expectancy and higher Expectancy Ratio.
He who thinks he can, and he who thinks he cannot, are both right. ~ Henry Ford