1: I'd have rated Haskell's concurrency as "best in class" thanks to its STM implementation. Other languages do have STM, but AFIAK only Haskell provides both efficiency and safety thanks to its type system. Other languages have to choose between tracking every variable (slow) and letting the programmer declare which values are going to be rewound if the transaction aborts (unsafe).
2: Your section on IDEs does not consider Leksah. I've just come back to this after a long time on Eclipse and Atom, and its now a mature IDE specialized for Haskell. You might consider bumping Haskell to "mature" based on this.