Would a 22,000-25,000-ton Des Moines make sense if the US heavy-cruiser line began from a 15,500-ton treaty limit?
Short answerYes; that displacement range is plausible within a few thousand tons.
NotesA higher treaty ceiling would normalize larger hulls, machinery spaces, protection, and magazines before the wartime design evolved. Des Moines could therefore grow into the low-to-mid 20,000-ton range without becoming an implausible departure from the preceding cruiser line.