Hmm.. maybe I'm not understanding right, but in the situation you describe you aren't going to get the objective in the current system either. If you can't push the enemy off of it, you aren't going to get it.
The problem was not about getting the objective, but about the combat drifting so far away from them that they become irrelevant. Right now you can push away the enemy, but not very far. On the border he's either forced to stop running and fight or to go for break-trough maneuver.
Maybe a solution would be to have not a central plain with objectives, but new objectives appearing as the battlefield moves along. Old objectives would become too far away and loose effect. As I understand those buoys and comm relays are supposed to be scattered throughout space anyway, so it would make sense.
That is a big problem - smaller, faster ships could just skirmish around and never be caught. It would make having small ships of your own to clear stragglers more important, but thats not really a solution. Controlling the nav buoys would be important. This is a problem with the current system as well (freaking Hounds never retreating when up against 3 destroyers...).
I think a different battle resolution mechanic could be a solution.
Just suppose you could strip and board destroyed ships in the combat screen (not practical during combat, simply because that is very dangerous for the docking ship).
Also suppose that a ship can start powering up its interplanetary drive at any time, but that would take some time during which weapons and shields are offline (and maybe is more vulnerable like with HEF). Once engaged, the drive can not be deactivated timely and is (almost) not steerable.
A battle would not end if any specific set of winning conditions is met, but if one fleet decides to leave the battlefield.
You could plunder your opponents remains and just ignore any fast ships that are out of your range, they would practically count as escaped. Your victory (or loss) would not be defined as a set of conditions, but by the financial gain or loss in that battle.
This might also explain (in-game) why
- ships have to slow down for combat in the first place (a fast traveling fleet could be ripped apart as they transit)
- ships can't use their interplanetary drives during combat (with semi exception of the onslaught line of ships)
- ships in a fleet travel so far from each other that they cant arrive on the battlefield at the same time ( different start times, high collision vulnerability combined with minimal maneuverability)