I think that to use sensei is not very smart. The point of dubbing and bringing it over to America is to get the American auidence to watch and hopefully pay for it. While most anime fans will understand and be fine with them using sensei, the casually fan would not...and might even be off put if all anime were not to become at least a little Americanized. That's just what I think though....While I would not mind them calling everyone sensei I could see where it would bug some people
I still say it's a really good dub but again that's just me we all have our own personal tastes.