The three main takeaways from Elliott Wave that I think are sound are that the market is driven by mass psychology, the reaction to the news is more important than the news and the market can always go further in one direction than you think it can.
Now, if you take those building blocks and build a trading system from them, I think you can do well.
Other than that, I don't even think that basic Elliott ideas like the distinction between "impulse" and "corrective" waves is valid. There are just "waves".
