LINQ is a query/update language for data structures. The beauty of it is that it can be used to read/update/modify vectors, lists, maps, etc. So, you just have one API to learn. And this API is easy to learn because it is modeled on SQL.
Adding a Haskell-like list comprehension (or Python-like) is not Java-ish anyway. You anyway need to add new syntax and since SQL is already known to most developers, I think it will be easy to learn for the most.