Oh crap! How could I forget Jaresh-Enyo? Duh!
I would think though that if Trek got an alien CO in the next series, it wouldn't be one with a lot of prosthetics--so as to not alienate any potential new viewers. Possibly Bajoran, Betazoid, Deltan, Trill or Vulcan.
Commander Austin Harris, First Officer, Deep Space Nine (by FltCpt. Bossco)
8.01 - Darkest Before Dawn
(Chapter 8 added, 12/09/2015)