All Regionals - Music needs to be playing from the moment the first person walks in the door. Would makes the event much more lively.
All Regionals - Need to have designated areas for banned-from-pit activities such as grinding, painting, soldering. The manual designates there will be such areas, but at every event I have been to they cease to exist.
All Regionals - Ban circular saws and cutoff saws over say a 6" blade from the pits, and use them in the "designated areas"
All Regionals - Allow Dremel grinding in the pits.
All regionals - Perhaps cut out all other sound (such as music) for important anouncements.
Los Angeles - Video screen needs to be bigger, brighter, and FOCUSED! A constantly updated video screen of any sort (even if it is a 13" TV) is absolutely mandatory on the PIT side of the curtain to show rankings and the such.
Phoenix - Don't change a thing.
All Regionals - Get Mark Leon as the MC and Don Knight as the announcer.

I'm not saying anyone else is no good, but these guys are truly awesome!