Vision is interesting in that it leverages the maximum speed with which it is easily possible to gather information about our surroundings in this universe. I believe that is what makes it special and very valuable. I also believe this aspect makes it a strong attractor for convergent evolution.

Language allows encoding and compression of information about the world, which is of course incredibly powerful and increases communication bandwidth enormously (as well as tons of other stuff).

I'd say that for high level cognitive processes, hearing and speaking were an important stepping stone because for some reason evolving organs that can generate relatively high bandwidth signals in audio seems to be easier than evolving something that does that for visuals (very few Teletubby screens on tummies in the natural world).

Interesting games to think about in this sense: Pictionary/drawing games and charades.