I believe, like Steve Yegge has said elsewhere, that programmers are lame, (and now paraphrasing) because they refuse to touch things that look odd.
Erlang's syntax may be more efficient, but a lot of people won't touch it becuase the syntax is unfamiliar. Elixir has a huge advantage in this. It might not matter to you specifically, but in the realm of adoption that is huge.
I mostly enjoy the syntax. Kind of hate that they made parentheses for function calls optional, especially since no-parentheses has ambiguous cases that behave weirdly (like with chaining syntax). Should be enforced.
Also, all the different import-related keywords are pretty confusing. Maybe that's improved though
Erlang's syntax may be more efficient, but a lot of people won't touch it becuase the syntax is unfamiliar. Elixir has a huge advantage in this. It might not matter to you specifically, but in the realm of adoption that is huge.
And honestly I really enjoy the syntax...