[Imp]

There are so many variables in this game getting a feature like this to work will always be hit & miss. Size of map, position of VHexes, mobile or not, force parity, game length etc.
I think it works well as a means to stop you dawdling especially for meeting engagements, deters playing as a delay letting them come to you. 6 points works OK for me in this case. For attack & assault in particular it makes it very difficult in WWII unless you increase game length which defeats the point I normally just accept the default.

Main use is in MBT to make Vhexes mean more if you want a game where Vhexes are important not just forces destroyed. Its down to unit cost current era MBT can cost 500 points so delayed objectives giving a few thousand points is not a big deal.
This is where it comes into its own, if you want a battle where destruction of the enemy is the priority leave them off but if you want Vhexs to be important turn it as high as 15

To be honest as well victory conditions are the one thing I take with a pinch of salt, draw, victory or loss are all that I really look at. You can work out quickly enough what the result would have been without timed objectives or if you want or make up your own victory levels.
At the end of the day I know how well or badly I played & that's my real gauge on how well the battle went not what the game decides.