They better keep the layout. Not just because it's more fun than Disneyland's layout, but because of the historical significance of being the first and original Space Mountain*.
And removing the music loops should be a non-starter. We've already lost too much evocative theme park music.
*Not that I expect Disney cares much about that last part, given that they're in the process of gutting the only WDW attraction Walt Disney directly oversaw...