Given the swoosh has accompanied the sent sound of messages since the dawn of iPhone in 2008 and few if any people are actually bothered about it, like me for example, it's not likely Apple is working on doing anything with the sound.
This is a user to user only forum. No one from Apple will see your post so if you want to share your thoughts with Apple, you can use this link --> Feedback - iPhone - Apple
Personally, I would suggest you not hold much hope for this to be changed. It would take a LOT of people complaining about this and there are just not many who do.