I don't feel like tackling this whole thing, but one example of a problem area:
I'd want swath or axe bow style outer hulls
These two are so different that they don't seem like solutions to the same problem set. Axe bows are meant to reduce pitch motions; in a trimaran, it's the main hull that is going to be the principal pitch generator, since it has most of the volume. The sidehulls are just following along, and you don't want them pitching too much differently from the main hull, because that creates torque on the cross-deck structure.
SWATH sidehulls on a trimaran is a terrible idea. Conventional sidehulls provide stability because their immersion and thus buoyancy rise as the ship rolls. SWATH hulls are the exact opposite -- assuming the SWATH pod is fully immersed, the struts holding it to the cross structure provide very little change in buoyancy in response to changes in immersion. So SWATH fails to serve the main purpose of a trimaran sidehull. People have tinkered with SWATH-like trimarans, but they are almost always the other way around -- a single submerged bulb center hull and two small conventional sidehulls to help keep the main hull upright (SWASH for single-hull rather than twin hull). But this shape is very sensitive to displacement changes, so you have to ballast for fuel consumed and so forth.
View attachment 678081
In any event, we can be very sure that
DDG(X) will be some variation on a conventional displacement monohull, based on the Navy's public statements, presentations, and preferences. the LCS trimaran only got a look becuase of the extreme speed requirement, which isn't in DDG(X).
The only question will be the extent to which it follows the design of DDG-1000 in terms of tumblehome and bow shape (the "Platypus" hullform). It seems clear \that the Navy is focused on a raked stem, maybe even a clipper bow, apparently for artic seakeeping? The hull and superstructure aft of that may be more
Zumwalt-like; a lot of published information is showing a hull with tumblehome down to the waterline aft, which is useful for RCS reduction. The superstructure is anyone's guess. The big Zumwalt-type monolithic deckhouse (below) has RCS advantages but limits arrangeable deck area, especially for trainable weapons like guns, RAM, and lasers. A more traditional superstructure (seen in earlier posts) is easier to place all those systems, but adds lots of potential radar corners unless very carefully designed.
(Note on this image: I'm not 100% sure it's actually associated with DDG(X). It's possible it was an analysis of alternatives for DD-21/DD(X) that they have dug up and used in modern presentations. If anyone knows the provenance better, I'd be very curious.)
View attachment 678082