Antesignani?

[A Terribly Harmful Name]

For example a 16th-century upper-class French traveler observed in his diary that a full Mediterranean meal roughly amounted to what was regarded as appetizers north of the Alps...

I would take that with a grain of salt, though. Cultural perception of food is not negligible and the larger use of meat north of the Alps as one of the main parts of the diet as opposed to south of it might have awaken the preconception that the more vegetarian oriented Southern diets were like the "appetizers" to the North.

Plus, animal protein - a key "building block" when size growth is concerned - was always in a particularly short supply around the Med. Not too much to hunt, not much to fish in the sea, not that good conditions for raising pigs and cattle for slaughter... Conversely, north of the Alps there was far more of all of that (particularly fish, on the shores of the Atlantic and the Baltic) for much more dispersed populations.

Take the face nutritional value, and many other important aspects to notice. First, the lack of animal protein in no way means a lack of healthy nutrition to the Mediterranean population, that even modern vegetarian diets can replace the protein lost with the lack of meat and that the supposedly larger "size" of Transalpine and northern populations, which is AFAIK supported by scarce evidence and samples, does not by any means translate into immediate battle superiority since no size or strenght will save you from being killed by a slashing sword or a piercing spear. I would rather say that the contrary is true: smaller and nimble warriors could dodge attacks better and faster than large and cumbersome brutes, if that's the model we would follow.

Also, recall that the defense skill score does not entirely stem from out-and-out ability to ward off blows with your shield and weapon, but also general readiness and ability to simply get out of the way of attacks - something that's generally easier when not weighrd down by armour. And also something you're going to pay that much more keen attention to when there's nothing to stop anything that connects...

I think that holds true only for the heaviest armor: mail and heavy plates and the likes. Leather and linen cuirasses seem light enough to allow reasonable movement freedom and do not hamper the movement of a phisically modest warrior as much as heavier armor would. And as for the "psychological" readiness, well, any line infantry would be aware that dodging is still 100% better than absorbing it no matter the circumstances.

Mind you, not every unit that under this logic was given the "agility" bonus due to considerations of inter-unit balance. Bataroas (the helmeted, shirt-wearing Gallic longsword guys) are and example, as the bonus would've driven their defense score total to a number unecceptably high for their price range and compared to some other, better equipped and hence more expensive, Celtic units. Botroas (the spiky-haired, topless longsword dudes) on the other hand duly got it.

See my post above: other than engine limitations I see no reason to apply the skill ratings as they are now.