The interesting part, to me, is that Arnsberg is known to defend his pitchers. Public criticism of players was a daily event last year. Whether it was position players or pitchers. So far, Mills has said the right things (i.e. The name on the front is more important than the name on the back - I wouldn't mind seeing the Astros drop last names on the back of jerseys) and Arnsberg seems to have actual leadership qualities (you don't throw your players under the bus).
Of course, the local sports-hacks will infer an intention, from the Astros hiring of Arnsberg, to go after Halladay in free agency or trade. Who knows, maybe Toronto needs a good DH.