The thing is, though, the environment never seems to play any role in starship propulsion. Our heroes never discuss "winds" of any sort, or subspace density, or even gravity - unless something catastrophically fails and for a rare once throws the ship at the mercy of the environment.
Not exactly. TOS did scan ahead for space and energy density (especially if it is something that they might have to fly through) and their "weather scans" spotted things like ion storms, etc. That might not exist in TNG because of different reasons but in TOS (and thus "Balance of Terror") the environment does seem to play a role in starship propulsion.