lethality plays a very important role in EB: if there are 2 units with a very similar attack value (let's say 10) but one has daggers (0.04 lethality) and the other has longswords (0.225 lethality), the second one kills enemy units a lot faster then the first one and in the end is much more valuable. AP (armor piercing) is another value that affects attack, its value depens on the enemies that you are facing (heavy armored armies can suffer a lot from AP weapons). Morale is valuable but not so much in EB as in vanilla IMHO, unless you play on high/very high on battles and you are forced to sustain heavy casualities, but it's still important when the unit is facing multiple or superior units (playing with Roman legions and some hellenistic-estern levy is still very different)