I agree with this. I feel that the descent completely kills the story and momentum of the rest of the ride. It's exactly what you said. It goes from grand to silly. It may be fun to see a poor picture of yourself in animation, and most people probably don't even notice the transition, but under it all, it totally undercuts the entire rest of the pavilion. The story is built in such a way throughout the rest of the ride that builds to that climax at the peak. But instead of reinforcing the message, instead of expanding upon the idea that we, all of us on the planet, are one human race, working together through communication to build the future, we're instead thrown into a silly little thing basically putting a terrible photo of us on the head of the Jetsons intro. It has no relation to the rest of the ride, the rest of the park, or anything else. Heck, it would be more tied into the message if it just told us all to whip out our cell phones and tweet #SpaceshipEarth. Oh god, I said it out loud and now it'll happen. It'll just be a bunch of people's tweets and selfies on the little screens with hashtags. Ugh, why did I do that?
Even with just coming down to various lights and colors listening to Tomorrow's Child, this underlined and reinforced the message of the pavilion. The music helped give an emotional connection to the message of the rest of the pavilion. It tied all of the stories told through the wonderful AA work and set pieces, it gave an underlying message of hope, and the music helped stimulate another part of the brain that helped form that emotional bond to the message.
I'm telling you. The impact of SSE is as much in the flow, the gradual build to that moment in the top, the script and score coming together in perfect timing to greet our Spaceship Earth, and then the descent which underscores the message. I don't feel the current narration hits that note correctly, and I REALLY don't feel that the descent does what it should do. It does the exact opposite. It turns what could be a moving experience into one that might be classified in the best terms as "well, that was fun".