You can't forget the fact that Hashirama repelled EMS Madara countless times, it's even suggested that they fought against each other only after Madara gained EMS (so both of their powers had similar potential).
From those 2 facts, it's much wiser and easier to get Hashirama's power.
We know that Oro (and others) made countless experiments and we know that countless Uchiha killed each other to gain MS, but many/most still failed. From what we know, it's hard to say which one of the process to gain power was more effective because we don't know the exact numbers, the only thing we know is that there are more people that were able to gain Hashirama's power than EMS.
question: did the sage purposely split his unified godlike power into two distinct parts and then pass them down to each son? or did it happen naturally or biologically on accident?
and if it was sage's son; for what reason, was he able to forsee something, or better yet, had a plan for his descendants to bring about world peace?
Qn: Could Oro's absorbtion technique that failed on Sasuke work on an ET zombie? I am thinking of Kabuto absorbing a ETZ and then having a body that never degrades and perhaps a blood line limit aswell....
Itachi would not fool for such a trick would he? becuase if Kabuto could absorb itachi, well....
who, other than me, got the distinct feeling that itachi finds kabuto and make him release the edo tensei so madara goes poof again, so naruto avoids fighting him?
it would be kinda cool if we see naruto fight madara evenly for a bit before tho.
Q: Here is a fun question given Edo Madara's abilities one has to wonder how do you think he died?
Given that Kishi likes to leave clues I think the answer might have just been given to us. Edo Madara stated he activated his Rinnegan just before his death. Well there is the major clue look what happened to Nagato overusing the power of the Rinnegan can lead to death.
I'm guessing Edo Madara died because he choose too and used Creation of all things to create Tobi or someone or something else. He clearly was aware of some kind of long term plan and Nagato was a part of it.
As to why he would sacrifice himself I can only imagine it was either an accident and he didnt realize he would die or he himself was dying perhaps from a disease.
What chakra type are you?