|Btw, you were saying Chapter 19 was a particularly challenging map with compact enemy groups earlier. I had a slightly different experience, one that ended in 3 turns. xD|
While I do think there's merit to your arguments based on what you've said, I also do think a significant part of this may legitimately be due to level discrepancy. I think your average unit was about 4-5 levels higher than mine at the time of that battle, and the lowest level unit I saw you using (level 35 I think? maybe I missed something) was substantially higher than my lowest (level 27 or 28, forget which at the time of 19). Given that the recommended player character level for the chapter is 37 (which from my experience is an overestimate anyway), and it seems like most of your units are starting it either at or above that level, I do think the strength of units plays an important role. My units just weren't capable of wiping out the enemies in the nearby vicinity of other enemies like yours were...and they certainly weren't capable of taking any hits from DK, even with rallies.