As I've mentioned before, I think that the meshing of the notion of "comics" with sequential images (a simple glossing of what I call visual language) actually hurts the perception of the graphic form by pigeon-holing it into a specific cultural context.
If this form of communication was actually used like a language there would be no reason people would call it "comics," and I certainly wouldn't have to be arguing that it is literally a language. Its recognition as a language would be self-evident from its usage.
This is why I always correct people who claim that we have a visual culture, or that people these days have a vast visual literacy. They have a familiarity with technological or cinematic representations, certainly. But, when 2/3 of America can likely not draw a coherent narrative sequence? Visual fluency, I doubt they have.
Truly, the need to argue for a "visual language" only comes out of a society where such usage is exceptional, not the norm. You can't have a culture where people claim visual communication is vast and prevalent, while at the same time have books arguing for increased usage of it.
Can you imagine books arguing for why people should be using language more? It wouldn't happen, because language is so prevalent and pervasive in society that to do so would be boring.
That's the extant of visual language I'd like to see — where someday people will look back on my writings and think its bizarre that someone had to argue for someone to even need to make the argument that its language.