What's more, it's an opportunity to lure a significant Dominion ally into the fold. Memory Alpha puts the movie around the same time as the DS9 episode 'It's only a Paper Moon', meaning that the Dominion forces are cut off from the Wormhole. The logistical problems this caused, combined with occupying the resource-starved Cardassian territories, are one of the major reasons, if not the only reason, for the Dominion defeat. If the lure the So'na away from the Dominion, weaking the Dominion forces in the process.Dominion 'colony' in the Alpha Quadrant was willing to outsource production of a substance as crucial to their war effort as Ketracel White, then the So'na must be able to produce sufficient amounts of it, and/or at a low enough cost to be worthwhile. Ispo facto, the Federation has a very good reason to
Well, it never occured to me that the Dominion War might be ongoing during this movie. In hindsight it really should have. This does not make the Federation seem the wiser for inviting their enemies into their space for a little collaboration on an immoral (presumably secret) project.
They could have effective made the Sona more villianous if they were tricking the Feds into hoovering up the ring for them with promised miracle cures. Picard and co make the hard choice to attempt to relocate the baku to save billions or whatever and they find out the hoovered up cure will only help the Sona cure themselves and leave the federation holding an empty bag. Then Picard and co would have to stop them.
Well, at the very least they could probably assure short-term regeneration, as occured with Geordi. Of course, that wore off once he was no longer under the radiation so...
I like Chuck's idea for improving the movie better. Actually have the crew be divided on the morality of the thing, so instead of Rua'fo calling the shots on the hunt for Picard and the locals, it's Riker.