@the-janus First, let me say that if there are awards for rules lawyering, you should be nominated. :grin:
I’m not going to go through this point by point, as I don’t feel it’s necessary. Instead, I’ll reply in general terms.
First, while the terms “choose a casualty” and “lose a unit” are admittedly not consistently applied, there is a definite difference in their meaning as applied to the defender (they are functionally the same for the attacker) implicit in the rules: choosing a casualty is the act of choosing a unit to be lost and moving it behind the casualty line, while actually losing the unit occurs in step 6 of combat when the units behind the casualty line are cleared. This difference exists only so that chosen units (behind the casualty line) are allowed to return fire before being eliminated.
Second, the idea that units behind the casualty line may be switched out after all dice are rolled is refuted by the statement on page 19: “After the defender’s counterattack, the defender removes all of his or her casualties that were behind the casualty line of the battle board and places them back in the tray.” There is no mention of exchanging these units for others. The idea that something is allowed because the rules don’t expressly forbid it is flawed. The rules don’t expressly forbid a lot of things, but they’re obviously not allowed (rulebooks at least provide parameters for things that are allowed unless expressly forbidden). If something as big as switching casualties were allowed, the rules would say so.
In fact, if it were the intent that casualties be finalized after all of the attacker’s dice are rolled, it would be much simpler for the rules to instruct you to keep track of all hits and choose casualties after all dice are rolled. Why specify choosing them column by column only to change them later? It just doesn’t make sense.
Finally, allowing the defender to switch out casualties before removing them would give him/her a significant advantage over the attacker, who must remove their casualties as they are chosen. If the defender were afforded such an advantage, it seems the rules would at least mention this.