Very interesting take on the subject, Chariklo
The JW claim is that the water baptism is a public declaration of the dedication of one's life to God. However, in JWspeak it means to promise to do the preaching work the way they want you to. The question about association with "God's bOrganization" came about more recently. Unfortunately in reality, like many facets of JWhood, it means more than they say... But don't you dare say it! An unbaptized person woudn't be subject to the same judicial procedures unless they truly wanted to be recognized as a JW. They could however, make the same "so and so is no longer recognized as one of Jehovah's witnesses" announcement and it would have the same effect.
As far as the significance of the occasion, I think that if one were to put aside the attachment to the bOrg, it would have equal significance to a person who wants to serve God. Either way it is a very important decision for someone who intends to live up to it, organization or not. Which is why myself and many others feel strongly about allowing children and immature younger ones to get baptized just because they can answer the questions in the OM book. I think the feeling among JWs is that to them it is the RIGHT decision, so it doesnt matter if the person making it isn't old enough to fully understand the implications.
Myself, I got baptized at 20 yrs old after being pestered about it by family and friends for years. I kept using the "Jesus didn't get baptized until he was 29"! Excuse. I could BARELY answer the questions in the OM book without help... Very poor instruction as a kid from my folks, and I had learned to tune out the meetings at a very yound age. I did not have the knowledge a person should have when making that decision, despite being a born-in. I had no interest in learning how to explain the doctrine, but there was a very pretty girl who I badly wanted to date (now my wife) and I had to get dipped to make it legit.
Either way, NOBODY ever intentionally dedicated their life to a CULT. And for that reason I dont feel like any JW baptism is legitimate in light of it's actual purpose and significance. They have no business making association with any one group a condition on one's baptism.