This was inspired from the responses on other threads and a special on PBS. People commented about a variety of features and flaws in regards to Nemo, but the subs stand out. Some people love the catroony look, others wanted the Atlantis feel. Some MC's miss the old yellow subs and their names, others go even farther back to the original paint job.
PBS had a special about a millionaire who wanted to build a private sub. Instead of going with the standard designs he made up his own. They used 2 large acrylic bubbles, joined at the center and sandwiched them between the top deck and steel hull. This technique offered amazing floor to ceiling views and has allowed researchers to study marine life in a "moving aquarium". Because of this design you are no longer limited by small tiny windows into the outside. The weakness is that you can't dive as deep... but for tropic seas the view can't be beat.
My belief is that the subs took the cheap way out. Instead of designing a new sub they just reused the standard model that has been around for decades. I would love to have seen a combination of this bubble sub and the Nautilus. Instead of being limited by small tiny windows you would be presented by a complete view. The equivalent of being IN the water, but still being dry.
To those who do not believe that Subs are "modern" enough to be in Tomorrowland I offer this. The deep ocean is the largest unexplored frontier left on Earth. It is believed that it ties the rainforest in "yet to be discovered species" and offers the best chance of larger undiscovered species (rainforest is mainly amphibians, arachnids, and insects). Underwater exploration may be ancient, but it is just as exciting and scientifically important as space exploration. In a world dominated by water... it makes sense to try and find out what's actually in it.
I put a banner that shows the sub and link to the actual PBS summary of the submarine episode farther down on the board!