The major concept I would like to explore here is the idea of the Hit assignment system, and the impact of different strategies in assigning Hits, and how different units as both attackers and defenders require different strategies with assigning hits to maximize your army's strengths.
Firstly (and please correct me if I get something wrong!) the core concept is that after rolling and modifying dice (after step 10.6) you have a pool of Accuracy, Mortal Strikes, and Hits to assign to your target. You first assign Accuracy to figure upgrades, then assign Mortal Strikes, then apply Hits. When you apply hits, you must assign them to the back row of trays unless you spend one Accuracy). Once you begin assigning hits you must continue to assign hits to the same figure until they have as many hits assigned as their defense (causing a wound) or until you run out of hits, and then may assign hits to another figure. Any units assigned enough gains a wound. The attack is resolved, figures are removed, trays removed, figure upgrades are replaced, and play continues. Lastly, a player cannot assign damage to unit in a way that would split the unit into one or more pieces.
There is a lot of discussion elsewhere in Rules Questions of what happens when a unit flanks, and how to take off trays so that a unit is no longer in combat, which is not what I would want to focus on. Rather, I want to talk about how we should assign the wounds. Let's look at my opening case for this: the Reanimates. Reanimates have the Regenerate ability, which allows them at the end of the turn to add figures back to a tray that has missing spaces. Let us say you are facing 2x2 tray Reanimates from the Core box. You roll for your spearmen and end up with 4 damage (2 threat, 2 damage rolled). Each reanimate has a single defense, meaning every wound we assign will remove a figure.
Option A: Remove all the figures from one of the Rearmost row on both rear trays. When this is done, the Reanimates will regain some of these at the end of the round. Also, because the tray isn't removed, they get their full strength of rerolls on their attacks.
Option B: Remove 4 figures from the same tray. When this is done, the whole tray gets removed, preventing regeneration. The Reanimates are reduced to only rerolling one dice instead of all dice on rerolls, and they can't regenerate since there are no empty spaces on the trays
TLDR: Clearly option B is preferred here. Thoughts/ideas/input!