In one of my 4x games, they actually had both. Star lanes where anyone could warp through and, if you bought it and had the energy cells to fuel it, a jump drive that could take you to any sector in range (depending on the number of energy cells).
Then again, it was slightly a different game. If I think back to games like Elite and it's successors that tried to do more 'realistic' things, it became so much you could not live without the 'time acceleration feature'.
In StarFleet Command they just used hexes you could move between and then just offered you missions. Sure, it was not space exploration but 'real' space exploration would be REALLY boring. Someone once compared two star systems in space as about comparable to two bees over Europe.
I personally have the feeling SF goes more into the 'mission based' direction. Kinda like the old Panzer / JaggedAlliance / Commandos / UFO EnemyUnknown|TerrorFromTheDeep. You set up your team, start the mission and then incrementally move on from there. Once done, collect the booty, RTB, etc pp.
Heck, with the theme of SF you could actually have multiple paths: a strict campaign ala Panzers / Commandos / JA: first mission 1 then 2 then 3 ... climax medals everyone parties; a dynamic story ala UFO (the path was kinda fix, but the events that lead up to the climax were dynamic) and finally a fully dynamic world ala SF:C, you go where you wanna go, do what you wanna do etc.