I think he just isn't a very good communicator (nor cares to be one). He was recently a guest at the excellent podcast Econtalk and you really needed to know his ideas from other sources to properly understand what he was talking about.

I don't think is arrogance or anything, it is just a skill that he doesn't have naturally and also doesn't care enough to practice and improve.

I think his ideas are strong enough to find an audience even without this skill. Contrasting him with a Malcolm Gladwell who, imo, reaches a large audience much more from his communication skills than from the power of this ideas, I think I prefer Taleb's style.