"any items of monetary value in the game will need to be signed with the Active key instead of the Posting key"
===> This is a great change !
When developing Splinterwars, even if I was using Steemconnect so as not to store any password, people were really worried about using their posting key. They were afraid that third parties may access and transfer their cards.
This update means that people will feel even more secured and will not be in doubt. This is great!
The double arena is a major update and great in the strategy part, but I wanted to point out that the security option that Splinterlands now provides is a good addition.