The lack of any other types then the VII's and the war "ending" in 43, IMHO, points directly to an expansion.
This is further backed up by this statement. ( from the press release posted here:
http://www.subsim.com/radioroom/showthread.php?t=165247 )
"Ubisoft continues to refocus its high-end games strategy by concentrating on more regular releases for its major franchises"
Now you can argue that this does not apply to SH5 but Im not sure, the key part to this sentence is "more regular releases".
That means expansions/DLC to me.
By the way Im not a huge fan of DLC... I see it as a cash grab for things that should have, and used to be, included in the original release.