Maxi's Element Affinities (Water Plot Hole?)

I just finished a re-read of UTOT and found myself wondering... is anyone else disappointed that we didn't get to know more about Maxi's elemental affinity toward water in addition to earth? It's mentioned multiple times that this is a rare combination, and I was actually looking forward to diving into this more, but it never happened, and I felt like it was only there so the Mages could call her "Sludge" in contrast to her more regal identity as Lady of Anatol.

I actually felt like the story completely ignores Water as a elemental magic, since the elemental Mages in Maxi's purview use earth (Annette, etc.), air (Ruth, Sidina), and fire (Agnes, Miriam). I cannot recall one Mage utilizing Water in the story. Moreover, Water as an elemental power is usually aligned with healing, and I expected this to be tied into Maxi's talents for healing, but again, Water is never mentioned. Am I missing something?