How large is Starfleet?

[Shamrock Holmes]

Maybe helm duty was upgraded for starships. Sailing on the sea is way different from sailing in space. Well it was definitely ugraded from Ensign Mayweather to Lt Sulu then downgraded to Wesley Crusher

What we see Sulu do is fly the ship and point the guns. Either task alone might be much more challenging than today - the former is in 3D, with significantly more options than in today's sedate 2D naval maneuvers, while the latter has never been handled by a single person in naval history.

Given certain advances in automation, it might well make sense to provide the ship with a single professional who essentially plays a first-person shooter game with the ship. His (hopefully suitably augmented) insticts decide the outcome of the fight that the CO merely orders started and stopped.

Timo Saloniemi

Given that Flight Controllers appear to include the duties of Helmsman, Lee Helmsman, Conning Officer, and depending on the era Navigator and/or Weapons Officer it makes a certain amount of sense for it to be a more broadly educated person at the controls than a junior enlisted (which explains Mayweather, Sulu, Dax, even Paris and maybe Nog at a pinch, but Weasley is still a bit of a headstratcher.)