Well if i were you i would not put all of my money into only one coin. Ethereum will be good you are right but you can make much profit if you put your split your investments in couple of high potential coins.
agree, you can do the diversification technique do not put all your eggs in one basket based on what i learned during my finance subject, i learned that all you can do is,
Don't concentrate all your resources in one place, because you could lose everything when it failed...
dont concentrate all efforts into one area too, It is wise to diversify your investments across different instruments,it will help you to earn much profit...