I think the Cretan archers may be running a bit fast, but not that much, as I looked at roman infantry running, their feet didn´t hover or anything on the tutorial map, concidering they are motion-captured this means the speed would be nearly 100% exact. On snow soldiers seem to be slower and if you look at their feet it looks more like they are too slow but too fast, like they move but don´t get forward. I wouldn´t slow all the infantry down to grandfathers, let your brothers or friends charge down the street with 20kg or so on their back and then tell me what you think.
i just want it to be realistic, not slower than the real thing just because you think people can´t run with armor.

PS: Keep in mind I´m not an expert and there is no offense intended by me, just my oppinion.