I prefer the doctors approach: "first, do no harm".
"The end justifies the means" is a useful concept that has been talked about many times. I would not dismiss it. I do not think it is reducing EA. I think it is communicating it with clarity, without confusing additions. It is its essence.
Someone claims (let's say to simplify they are not lying) to want to maximize their good in the world, for that to be accomplished they need to do something that somebody does not approve of (only caring about money, being rude to you, whatever it is). That is literally "the end justifies the means", where the end is "doing good in the world according to model x".
More often than not, that is just an excuse to do something despicable under the excuse of the future good.
> Evidence-based data to determine how they can do the most good
This is a model. If the model is wrong you might cause more harm than good. So, if EA is honest to work this model needs some proof that it works. Otherwise EA is only successful in becoming popular as an idea, not in accomplishing its stated objectives.
Does earning a lot of money and donating it to charities create more good? I am not sure. Maybe earning less money and care for people in your everyday life would create more good.