Due to the scale of Campaign Series the assault function and even the units themselves can only be an abstract representation of actual combat. 250 meters is a lot of room and many assaults conducted in CS in real life would probably be close fire fights.
If my opponent is able to move a half track around my unit stack and assault my disrupted units from opposite sides I put that down to the enemy having numerical superiority in the area. Historically I doubt half tracks would help a close assault by driving around to the rear of a position while their infantry was engaged but if my flanks are not protected then either I didn't properly position my troops or the odds were very much stacked against me.
As for objective hexes I think they work best with the exit hexes. Either one side breaks through and exits the map or they don't. As for objective hexes in cities, crossroads, etc, I think they work well during game play as folks will maneuver to gain superiority there. I would say the objective hexes do lead to some "gamey" play the last couple of turns. For instance I might have overwhelming firepower overlooking an objective hex but my opponent is able to send in a suicide mission on the last turn to take that hex for the points. I also put the last couple of turns down to an abstract representation of real life. If my opponent is able to sneak in a lone unit on the last turn to a major VP hex then shame on me for not being able to protect it better or cover the approaches.
For true "historical" play I would just set up some ground rules before hand with your opponent. For instance Leto's Half-track rules are good:
https://www.theblitz.club/message_boards...?tid=42435