I was watching TNG the other day for the first time in years and I had to ask myself if there is any need to helm or navigation. Surely the captain/first officer could just tell the computer where they want to go and when they want to arrive by, and the ship can steer itself.
I was just gonna post this same comment. TNG LCARS era has quite a bit of verbal ordering of the computer. I can easily see the captain's usual order "set course 213 mark 15, speed warp six" being given to the ship's computer for execution. LCARS systems seem advanced enough to handle such an order, although we've never really seen it replace the helmsman.
Plus, there was early TNG Tech Manual info about the ship being advanced enough that one could pilot it with a PADD from any location. If it was that easy/advanced, it would again seem to diminish the role of helmsman--at least in TNG era.
The way I see it is:
1. Captain gives command: "Go thata way."
2. Helm/navigation chooses the best route to go that way (around space hazards, best warp paths, etc).
3. Computer takes care of all the minute microsecond-level details so the ship doesn't tear itself apart when it hits a bump in space-time.
4. Engineering crew makes sure the computer is doing its job re. not blowing up ship.
In normal situations this is simple stuff; the computer could do it without the helmsman, but they are there to override the computer if it does something off, and to gain experience, etc. You usually see a senior member of the crew jump into the pilot seat in a time of crisis, as they would have more experience and skill in the above.
Starfleet seems to have something against AI, and robots in particular. They don't even seem to have them to do routine maintenance, like clean the waste processors. I wonder if the Telarites had some sort of robot apocalypse in their history or something