I've been doing Rails development for ~10 years and maybe it's just a sign that I'm getting older, but for me the biggest problem isn't Rails, it's Ruby.
In the past year or so I've done a lot of more modern JS development (with Babel and Flow) and toyed around with Elixir and ReasonML. Ruby hasn't seen much change in the past couple of years (granted it's much more mature than Elixir/Reason) and while it was a boon to developer productivity and happiness compared to the languages of the time, I think we've probably found a better balance in type systems these days than Ruby and the like did at the time.
Maybe it's just legacy codebases, but manually reasoning about types is huge time sink and are one of our leading causes of production errors. Explicit typing also informs better design (I've seen many a Ruby method have return type of `String | Array | nil`). Unit tests help, but why outsource that to tests and guard statements (where you have to check every type) when a computer can do that for you?
In the past year or so I've done a lot of more modern JS development (with Babel and Flow) and toyed around with Elixir and ReasonML. Ruby hasn't seen much change in the past couple of years (granted it's much more mature than Elixir/Reason) and while it was a boon to developer productivity and happiness compared to the languages of the time, I think we've probably found a better balance in type systems these days than Ruby and the like did at the time.
Maybe it's just legacy codebases, but manually reasoning about types is huge time sink and are one of our leading causes of production errors. Explicit typing also informs better design (I've seen many a Ruby method have return type of `String | Array | nil`). Unit tests help, but why outsource that to tests and guard statements (where you have to check every type) when a computer can do that for you?