I think you are right about that. My 41 gallon fresh water tank lays against the rear bumper. That of course is not ideal for over-all vehicle handling when full of water. It is easy to conclude that is why I needed to have some suspension upgrades to correct some handling concerns.
I think the newer design turns the tank 90 degrees and is mounted against the bathroom wall which sacrifices the depth of the compartment. The storage door is then slid rearward where the tank used to be. The area to the right by the rear tires gets utilized by the furnace. The end result is the fresh water tank is placed near the center line of the rig and more forward. That is much better for weight distribution, but sacrifices significant rear storage to achieve it. I also wonder how well it fills. I have read of some "burping" issues where air gets trapped and then the water can't get into the tank without using a filler thingy.
I wish someone with a newer 2350 would "check" me on my accuracy.
Here is a picture of a 2012 2350. Note the locations of the water filler door, the main storage door, and furnace service door.
I wish I had a better picture of my 2007, but note the water filler door is rearward and the storage door is forward. My furnace is on the other side of the motor home. I do not have burping issues when filling the fresh water tank because the tank is right up against the filler door.
