I said this before: phoenix is the new Rails, and that is not a good thing. Phoenix will end up bogged down with the same great "ideas", hex will end up chock full of crap like gems.
Elixir ok, phoenix not so much.
And yes, phoenix will end up bogged down like Rails, and hex will end up chock full of crap, it is the Rails developer mentality I'm afraid, they just can't help themselves.
I like to think of Phoenix as an interface to my app. It's less intrusive than Rails.
You don't have to use Ecto (the "ORM" thingy that is actually not an ORM) to get get the full power of Phoenix, it's also decoupled.
Regarding Hex, it's like every package managers out there. Sure you can publish anything. Rubygem is full of crap, npm is full of crap etc.. But I can also find some very small and focused libraries that wouldn't have been published, had a quality filter been setup to publish anything.