Since the last series ENT had a Vulcan T'Paul I will go out on a limb and figure it will not a Vulcan as part of principle cast as a crewmember on the bridge.It was never about having an AI character, it was about having a non-human/outsider. It's a pretty standard sci-fi trope, and we've seen it done in every iteration of television Trek. Yes, in TNG and Voyager it was an AI, but it in TOS it was Spock, in DS9 it was Odo and in ENT in T'Paul.
AI and Machine Learning are very big right now in near future tech and looking 25 years from now so I'm going to guess they will put something like that in the show. I am also very interested in the computer's voice since we no longer have Majel Barret to voice the ship's computer.