If people ask me "What's Aikido?" I sometimes say it's the martial art that Seagal uses in his early movies, and that he is/was a 7th dan black belt in Aikido before he got into movies. I also say that some people describe it as origami with people.
Does Aikido need someone equivalent to spread the rowing word? Hmm. Kung Fu took an upswing in North America when Carradine was the grasshopper: Kwai-Chang Kaine (sp?) - do we need a TV series where a wandering ex-uchi-deshi saves damsels in distress while thrashing baddies about with aikido techniques? If there were lots of flashbacks to - oh - say - learning to tie his obi, learning to sweep the dojo, learning to bounce off the floor, learning (and struggling with) Ikkyo/Ikkajo or whatever, learning to fold his new hakama, and so on, who knows - it might work, but it probably wouldn't in today's environment because of the lack of gore and machine guns...
well that programme would certainly appeal to me but then again I love Budo!
Seagal does have a TV series now called True Justice set in Seattle. I've seen a few episodes, it has all the hallmarks of a Seagal film with a fairly strong connection to his Asian background as a young man. But I'm not sure Seagal carries the same influence he once did. If he were to appear in the Expendables 3 that would definitely boost his stock again!