Yeah, the usage of V instead of 5, as well as the ESRB rating mentioning drug use (the first in the series to mention drug use), had alot of people expecting Vietnam. On top of that, the EA/DICE marketing team had teased a brand new setting for the franchise on the official Battlefield website, so alot of people were hoping for the Korean War, the only major war in the 20th century to have not had a video game based on it so far.
WW2 is not a new setting for the Battlefield series, they already did it with Battlefield 1942 and 1943. Why did they not just name it Battlefield 1944, a name that was in-line with the other WW2 Battlefield's, and announce the name last week, instead of naming it V and teasing a new setting for the franchise, getting people hopes up for other settings for no reason?
No, Already in march people reported that the game will be set in WWII with V for victory. A new setting probably locations we never been to or new modes like battle royale.