I just don't see how it can be a "good" attraction using that space and ride system.
The ride system is deeply flawed and never worked as intended. It's all well documented in an interview with one of the imagineers in an old article over at mouseplanet. They only got funding because of Rhode claiming they could make it go backwards at the presentations to sponsors.. something that was NOT planned. So WDI had to figure it out.
They "did" so to speak, but they had no idea how it would change the pace of the boats through the ride. They went much much faster - Maelstrom is supposed to be a slower El Rio or Pirates type boat ride until the drops. Instead it zips along fairly quickly, and there's no functional way to slow it down. Pump less water, the flumes goes down and the boats bottom out. Pump enough water, the boats zoom past. There is no solution short of a new ride system.
So keeping that in mind, you've got very small spaces to show very few scenes at a very abrupt pace. This lends itself to long musical moments.. how? I just don't see it happening. At least not "well."