Well, the strengths of languages like C# and Java are extensive libraries along with static typing and the code completion that enables. Object orientation also helps with code completion, because the you normally have the noun to hand in a local or a field before trying the operation.

Java does have a fashion for verbose identifiers, and C# has picked up a little bit of it, although the ceremony is less in C#. Ceremony can be macro'd away, but verbose identifiers are more problematic.

I'd also argue that the scope and complexity of big Java apps is often larger and broader than most C++ apps: more libraries used, and at a higher level of abstraction. When you dance across the surface of many different libraries, good code completion makes your life easier. That is, the chief problem code completion solves is not intrinsic to any given language, but rather the absolute number of symbols used.

When coding languages like Ruby, I rely heavily on the interactive console (Pry for Ruby) in order to get the moral equivalent of code completion.