Carlos - the watch analogy may not be accurate, the "waterproof" watches tend not to be weathersealed after a battery change due all to often to the kid in the mall, who is changing the battery NOT having the right tool to make it so. Whereas, if the watch is brought to a real jeweler or watchmaker, who does have the right equipment, they can be made "sealed" again. .....also I feel you are correct on one thing, if Canon or Nikon want to truly make a professional model with a tilt/swivel LCD and make it durable, some one could and would make it work....JMHO....
p.s. my father was a watchmaker.....