I have ALWAYS said that the quality of current English Dubbed anime would be 10x better if it adopted the mindset that Disney and Pioneer had where they would look for talent outside of the pool of already established talent.
While this does present certain problems for continuity later on in shows that continue, ultimately, the biggest hurdle to this great idea is the almighty dollar, companies want to spend as little as they can on a show, which clashes with looking for stage actors especially, who actually get paid for the majority of their work outside of anime, lol.
In the case of Ai, it might come down to how committed the company, or people working on the show are. There are two cases that I know of, of commitment to a project. The director of Metal Gear Solid spent his own money to bring back the voice actors for the remake of the first game. Also the people for Hellsing brought back almost all the voices back for Hellsing Ultimate which is awesome. Whoever gets Tenchi Muyo, will have to live up to the bar if they want to make money, 20 years of still being remembered, Negishi directing Ai, loyal fans, and the funded and success of Tenchi Muyo Ai by the city of Takahashi. If they get too cheap and half-@$$ the voice work for the dub, they might as well be asking to be flipped off.
