I'm in agreement with "Another DoM is going to obtain Water".
With BRD being DoW, and BST/SMN being the only announced DoM, I can very well see Water being reserved for another DoM class/job.
On a side note, I'm surprised they didn't give "Light" comboed elements to CNJ,. and "Dark" comboed elements to THM.
(For those that don't know, Dark and Light SCs in XI had 3 elements tied to them, and this carried over to THMs dark/light damage.)