Winnebago has chosen and they probably have maximized their Travato. There are factors of room. The Winnebago ERA 70A has a capacity of 70 gallons total vs. Winnebago Travato at 51 without compromise on the size of the refrigerator. Same company, same engineers and same drive for lowering costs. The lower floor is one big factor of room and putting a tank inside sacrificing storage is telling. One other factor is LP gas capacity is considerably greater in the ERA than the Travato. I would venture to guess the ERA 70A has considerably more storage capacity under its beds than the Travato and definitely has more inside cabinet and drawer storage. If like my Great West Van they could probably carry most of that 7 gallons of water stored inside their cabinets. We store 4 gallons that way for fresh drinking and cooking water in one cabinet below our kitchen sink. That's more than we need between fresh water fill ups with our greater capacity water tanks.
The Travato will never have the capacities of a Sprinter because of the lower floor and simply because of how much load they can physically carry which is also considerably less.
The Ford Transit by all indicators will also have greater capacities without strange compromises that have come to be expected in American designed Class Bs. Why? Because it is more similar in size and design to the already proven capacities of the Sprinter. It is not the designer, and it is the chassis limits.