I've been thinking about this along with the rest of you since the announcement. The only justification I can come up with for the new name (insertion of "Hollywood") is because of partnerships beyond Disney. In other words, with the Lucasfilm areas (Indiana Jones, Start Tours, Star Wars Weekends, etc.), as well as the Great Movie Ride, Disney wants to be able to wrap a name around it all that's logical. If they are planning to enhance "The park formerly known as MGM", then Hollywood may make sense.
I've read a lot of rumor & fact threads talking about Star Tours 2.0, a possible Indiana Jones ride, permanent stages for the Jedi Knight training, etc. Since these are non Disney, but have a tie-in through Hollywood, it makes sense to me. I realize that filming is done globally and the concept of Hollywood is Cali-centric as I too thin Cali when they say Hollywood. But I think the big approach is to tip the hat to the epicenter of movie/television/animation studios in general.
Could work well. In all honesty, I'm going to miss the old Hollywood we've known of the "MGM" era.