Tricky one this, I think. It would certainly make sense for wars to end as draws once it's not practical for one faction to get a sufficient lead over another. It would also certainly make sense for conflicts to only start if at least one of the factions owned an asset. I'm pretty sure both those changes would be very popular out here in Colonia, as they'd cut out 95% of conflicts and shorten a lot of the rest, making it a lot easier for factions to sit peacefully in their systems without the constant risk of asset-free wars.
But ... on the other hand, without wars and conflicts putting a brake on expansions, or dragging factions down to retreat thresholds, you'd likely see rapid chain expansion from the controlling factions of any reasonably consolidated low population system, which would fill most systems up to 7 factions very quickly. It would also be much easier for undermaintained factions to sprawl uncontrollably - whereas now a war chain leading to collapse is more likely.
Additionally, there are a lot of Engineering-related items which are easiest to get from CZs. A change which made CZs much rarer would potentially be unpopular in its own right, but would also concentrate players to the smaller number which did exist.
If a faction is under 5% and owns a property the controlling faction should be contending them to claim it.
I think that would make it too easy for controlling factions in most systems to consolidate all stations under their control, even without conscious player intervention ... which would then with the other changes largely eliminate inter-faction conflicts in the longer term. There's perhaps a question of whether a faction presently in control of the system would want to risk a control war - in which it must stake the controlling station! - just to win a minor outpost.
Mixed-ownership systems are I think more interesting to visit from a non-BGS point of view, too, and this change would tend to make them unstable.