I see no problem using the word "anniversary". Anniversary isn't necessarily positive or negative - it's neutral, indicating simply that something happened a certain number of years ago. I see it as often referring to things like national tragedies such as the 9/11/2001 attacks as I do for something celebratory such as a wedding.
I do agree, however that "Premium Quality Playing Cards" means as much to me as "The check is in the mail." Were they certified by some quality review board, or did someone's aunty say they were really nice? It's meaningless in this context.
I'd be surprised if you didn't include the flag of France on the new tuck - a large amount of the fighting took place in that nation. You're using the wrong US flag - the 35-star flag you depicted was taken out of commission on July 3, 1865; for the full duration of "The Great War", the flag had 48 stars on it, in a grid 8 stars wide and 6 stars tall.
The box back looks a bit bland as well. Perhaps you could depict flags of the US/UK/Fr alliance on the front, with the opposition on the back? Or maybe a map of Europe at the time war broke out as a wraparound?
Now, what do the cards look like - faces and backs? Who will be your printer?
Well grandma said they looked like good quality and frankly, I trust her judgement
But It's just there because I think it adds to the somewhat vintage look of the tuck case. It isn't supposed to entice people to buy directly. Also, I am still upset about france's involvement in this deck because the way the deck features work, there simply wasn't enough room. The situation with the American that is on one of the cards in the deck does in fact have the correct 48 stars. That tuck case image is an older model.
But thanks for all the tips guys, keep em' coming.
EDIT: I'm trying to show you the entire deck but I'm having trouble converting them from a PDF to something Imgur will accept in high quality.