I'm not sure about Emerald Princess, but the last two Princess ships I have been on, Sapphire and Island both had Texas hold 'em; it is so popular now I can't imagine them missing a chance to capitalize on that popularity.
As for The Sanctuary, I haven't benn on a ship yet that has that new (re)venue. You would have to see for yourself if you think a half-day of peace and quiet is worth $15. They claim it is so popular, they had to add the charge to cut down demand;
could that be why they charge $1.50 for soft-serv ice cream as well? To cut down demand?
I'm sorry. I am a little tired of being nickel-and-dimed by my favorite cruise line. Well, maybe The Sanctuary it worth it--it sounds like more than just a quiet place. I'd like to hear from someone who has experienced it.
Anyway, should be fun going with a large group. We had several groups and large families on our last trip and they were having a ball.
Have a great cruise!