Thanks for the welcome, Razor. My view on the pursuit of a retreating army was that it would be a rare occurrence (and it has indeed been rare for us), as usually a defender will only try to prevent the attacker from retreating untouched if the first round(s) of the attack went dreadfully wrong for the attacker (to the point that the attacker’s army was now only equal to or weaker than the defending army, assuming the attacker had some sort of numerical advantage when the attack began).
While this is not an impossible scenario, the likelihood of the defender trying to cut off the escape is made increasingly less likely by the fact that on their turn, they might be able to bring in units from multiple territories to counter attack (not to mention nearby air units) that certainly wouldn’t be available to them while defending/pursuing on the opponents turn. I don’t think this constitutes pulling double duty, as it is not necessarily a free shot at the retreating army out of turn, but usually just a continuation of the combat that the enemy had already engaged in. Any casualties suffered by the retreating army would obviously only be taken out of the forces that attacked (not from units that stayed behind), and any units not taken as casualties would be allowed to return to the territory they originated from as normal.
I agree with your point that naval combat and land combat was drastically different for obvious reasons, and “lose touch with” was probably not the best choice of words. As you pointed out though, there would certainly be ways or opportunities for an army to retreat (relatively) untouched, such as laying mines, and I would possibly add certain elements of weather and nightfall to that (not that no one ever fought in the snow/rain or dark, but it would have hindered things to a point).
All things said, all the die rolling for this would only happen if the defender chose to try and engage the retreating army. I do think maybe it could be more fairly balanced to allow the attacker to retreat if they wanted, but should still allow the defender at least a chance to snipe at them while they leave. If they defender gets a “successful” roll allowing it to continue the combat, basically it just represents the case that an attacking force overextends itself and is unable to form an orderly retreat, allowing the defender the continue to engage them while they fall back. Does this seem better?
Roll (if defender wishes to pursue):
1-3: The retreat is successful and you are unable to pursue. Combat ends.
4: Enemy army retreats but tanks and mech. infantry are able to pursue for a short while. May conduct one additional round of combat with only these units (if the defender wishes).
5-6: Enemy army is unable to form orderly retreat: continue all combat for one round (if the defender wishes)