Just read the Dual Blade Q&As and saw this:
Q: Will the Dual Blade Cash Shop shareable with Explorers?
A: Dual Blade characters will not be able to share their Cash Shop.
Q: Can Dual Blade characters enter Crimsonwood Keep Party Quest?
A: We haven’t made changes to the Crimsonwood Keep Party Quest to allow additional classes. Only the main Explorer classes will be able to participate. This does not mean that this will remain this way forever. 😉
This will really affect the number of Dual Bladers and the number of people interested to. No CWKPQ means no MoNs which is a lot of useful damage. Also, with dual pendants coming out soon, this would be huge.
Also, no sharing cash shop means no xferring your nx clothes or pets. 😦
See the Q&As here.